Polymers in Tissue Engineering

A topical collection in Polymers (ISSN 2073-4360). This collection belongs to the section "Polymer Applications".

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Editor

Department of Bioengineering, School of Engineering, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
Interests: biomaterials engineering; hydrogel nanocomposites; in vitro cell culture platforms; protein structure and function
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

Biomaterials are a cornerstone of tissue engineering and are designed to provide an architectural framework that mimics the native extracellular matrix to support cell growth and maturation and the formation of functional tissues. The use of polymer-based biomaterials (natural, synthetic or composite) in tissue engineering has increased substantially in the past couple of decades. This growth has partly been supported by the convergence of seemingly unrelated technologies (including surface modification, high-throughput screening, micro- and nanocomposites, additive manufacturing, etc.) that has enabled the development of sophisticated, integrated approaches and toolsets to address complex challenges in tissue engineering. Applications of polymers are no longer limited to the design and development of physical templates; rather, polymeric scaffolds are now being designed to also provide biochemical and biophysical cues to facilitate and modulate cell proliferation, differentiation, and maturation into functional tissues. These advances, alongside the progress made to improve their applicability as drug delivery vehicles, implant materials, and 3D printed constructs, set the stage for polymer-based biomaterials to significantly impact tissue engineering in the years to come.    

This collection aims to be an interdisciplinary forum for researchers to share developments in the synthesis, engineering, and characterization of polymers for applications in tissue engineering. Original research articles and reviews are welcome, as are commentaries and perspectives on the future trends and challenges in this field.

Dr. Prashanth Asuri
Collection Editor

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Related Special Issues

Published Papers (46 papers)

2023

Jump to: 2022, 2021, 2020, 2019

35 pages, 5683 KiB  
Review
Additive Manufacturing and Physicomechanical Characteristics of PEGDA Hydrogels: Recent Advances and Perspective for Tissue Engineering
by Mohammad Hakim Khalili, Rujing Zhang, Sandra Wilson, Saurav Goel, Susan A. Impey and Adrianus Indrat Aria
Polymers 2023, 15(10), 2341; https://0-doi-org.brum.beds.ac.uk/10.3390/polym15102341 - 17 May 2023
Cited by 9 | Viewed by 4451
Abstract
In this brief review, we discuss the recent advancements in using poly(ethylene glycol) diacrylate (PEGDA) hydrogels for tissue engineering applications. PEGDA hydrogels are highly attractive in biomedical and biotechnology fields due to their soft and hydrated properties that can replicate living tissues. These [...] Read more.
In this brief review, we discuss the recent advancements in using poly(ethylene glycol) diacrylate (PEGDA) hydrogels for tissue engineering applications. PEGDA hydrogels are highly attractive in biomedical and biotechnology fields due to their soft and hydrated properties that can replicate living tissues. These hydrogels can be manipulated using light, heat, and cross-linkers to achieve desirable functionalities. Unlike previous reviews that focused solely on material design and fabrication of bioactive hydrogels and their cell viability and interactions with the extracellular matrix (ECM), we compare the traditional bulk photo-crosslinking method with the latest three-dimensional (3D) printing of PEGDA hydrogels. We present detailed evidence combining the physical, chemical, bulk, and localized mechanical characteristics, including their composition, fabrication methods, experimental conditions, and reported mechanical properties of bulk and 3D printed PEGDA hydrogels. Furthermore, we highlight the current state of biomedical applications of 3D PEGDA hydrogels in tissue engineering and organ-on-chip devices over the last 20 years. Finally, we delve into the current obstacles and future possibilities in the field of engineering 3D layer-by-layer (LbL) PEGDA hydrogels for tissue engineering and organ-on-chip devices. Full article
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19 pages, 3863 KiB  
Article
Chitosan Grafted with Thermoresponsive Poly(di(ethylene glycol) Methyl Ether Methacrylate) for Cell Culture Applications
by Natun Dasgupta, Duo Sun, Maud Gorbet and Mario Gauthier
Polymers 2023, 15(6), 1515; https://0-doi-org.brum.beds.ac.uk/10.3390/polym15061515 - 18 Mar 2023
Viewed by 1145
Abstract
Chitosan is a polysaccharide extracted from animal sources such as crab and shrimp shells. In this work, chitosan films were modified by grafting them with a thermoresponsive polymer, poly(di(ethylene glycol) methyl ether methacrylate) (PMEO2MA). The films were modified to introduce functional [...] Read more.
Chitosan is a polysaccharide extracted from animal sources such as crab and shrimp shells. In this work, chitosan films were modified by grafting them with a thermoresponsive polymer, poly(di(ethylene glycol) methyl ether methacrylate) (PMEO2MA). The films were modified to introduce functional groups useful as reversible addition–fragmentation chain transfer (RAFT) agents. PMEO2MA chains were then grown from the films via RAFT polymerization, making the chitosan films thermoresponsive. The degree of substitution of the chitosan-based RAFT agent and the amount of monomer added in the grafting reaction were varied to control the length of the grafted PMEO2MA chain segments. The chains were cleaved from the film substrates for characterization using 1H NMR and a gel permeation chromatography analysis. Temperature-dependent contact angle measurements were used to demonstrate that the hydrophilic–hydrophobic nature of the film surface varied with temperature. Due to the enhanced hydrophobic character of PMEO2MA above its lower critical solution temperature (LCST), the ability of PMEO2MA-grafted chitosan films to serve as a substrate for cell growth at 37 °C (incubation temperature) was tested. Interactions with cells (fibroblasts, macrophages, and corneal epithelial cells) were assessed. The modified chitosan films supported cell viability and proliferation. As the temperature is lowered to 4 °C (refrigeration temperature, below the LCST), the grafted chitosan films become less hydrophobic, and cell adhesion should decrease, facilitating their removal from the surface. Our results indicated that the cells were detached from the films following a short incubation period at 4 °C, were viable, and retained their ability to proliferate. Full article
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2022

Jump to: 2023, 2021, 2020, 2019

17 pages, 4727 KiB  
Article
Tribological Evaluation of Silica Nanoparticle Enhanced Bilayer Hydrogels as A Candidate for Cartilage Replacement
by Mohammad Mostakhdemin, Ashveen Nand and Maziar Ramezani
Polymers 2022, 14(17), 3593; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14173593 - 31 Aug 2022
Cited by 2 | Viewed by 1300
Abstract
Polymeric hydrogels can be used as artificial replacement for lesioned cartilage. However, modulating the hydrogel formulation that mimics articular cartilage tissue with respect to mechanical and tribological properties has remained a challenge. This study encompasses the tribological evaluation of a silica nanoparticle (SNP) [...] Read more.
Polymeric hydrogels can be used as artificial replacement for lesioned cartilage. However, modulating the hydrogel formulation that mimics articular cartilage tissue with respect to mechanical and tribological properties has remained a challenge. This study encompasses the tribological evaluation of a silica nanoparticle (SNP) loaded bilayer nanocomposite hydrogel (NCH), synthesized using acrylamide, acrylic acid, and alginate via modulated free-radical polymerization. Multi-factor pin-on-plate sliding wear experiments were carried out with a steel ball counterface using a linear reciprocating tribometer. Tribological properties of NCHs with 0.6 wt% SNPs showed a significant improvement in the wear resistance of the lubricious layer and a low coefficient of friction (CoF). CoF of both non-reinforced hydrogel (NRH) and NCH at maximum contact pressure ranged from 0.006 to 0.008, which is in the order of the CoF of healthy articular cartilage. Interfacial surface energy was analysed according to Johnson, Kendall, and Robert’s theory, and NCHs showed superior mechanical properties and surface energy compared to NRHs. Lubrication regimes’ models were drawn based on the Stribeck chart parameters, and CoF results were highlighted in the elastoviscous transition regime. Full article
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11 pages, 5745 KiB  
Communication
Tri-Layered Vascular Grafts Guide Vascular Cells’ Native-like Arrangement
by Xingyu Yuan, Wen Li, Bin Yao, Zhao Li, Deling Kong, Sha Huang and Meifeng Zhu
Polymers 2022, 14(7), 1370; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14071370 - 28 Mar 2022
Cited by 10 | Viewed by 1939
Abstract
Bionic grafts hold great promise for directing tissue regeneration. In vascular tissue engineering, although a large number of synthetic grafts have been constructed, these substitutes only partially recapitulated the tri-layered structure of native arteries. Synthetic polymers such as poly(l-lactide-co-ε-caprolactone) [...] Read more.
Bionic grafts hold great promise for directing tissue regeneration. In vascular tissue engineering, although a large number of synthetic grafts have been constructed, these substitutes only partially recapitulated the tri-layered structure of native arteries. Synthetic polymers such as poly(l-lactide-co-ε-caprolactone) (PLCL) possess good biocompatibility, controllable degradation, remarkable processability, and sufficient mechanical strength. These properties of PLCL show great promise for fabricating synthetic vascular substitutes. Here, tri-layered PLCL vascular grafts (TVGs) composed of a smooth inner layer, circumferentially aligned fibrous middle layer, and randomly distributed fibrous outer layer were prepared by sequentially using ink printing, wet spinning, and electrospinning techniques. TVGs possessed kink resistance and sufficient mechanical properties (tensile strength, elastic modulus, suture retention strength, and burst pressure) equivalent to the gold standard conduits of clinical application, i.e., human saphenous veins and human internal mammary arteries. The stratified structure of TVGs exhibited a visible guiding effect on specific vascular cells including enhancing endothelial cell (EC) monolayer formation, favoring vascular smooth muscle cells’ (VSMCs) arrangement and elongation, and facilitating fibroblasts’ proliferation and junction establishment. Our research provides a new avenue for designing synthetic vascular grafts with polymers. Full article
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6 pages, 208 KiB  
Editorial
Recent Advances and Future Challenges in the Additive Manufacturing of Hydrogels
by Chris Danek
Polymers 2022, 14(3), 494; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14030494 - 26 Jan 2022
Cited by 2 | Viewed by 2108
Abstract
The emergence of additive manufacturing, otherwise known as 3D printing, was predated by significant advances in the understanding and controlled engineering of hydrogels [...] Full article
14 pages, 6816 KiB  
Article
Biocompatible and Thermoresistant Hydrogels Based on Collagen and Chitosan
by Pablo Sánchez-Cid, Mercedes Jiménez-Rosado, José Fernando Rubio-Valle, Alberto Romero, Francisco J. Ostos, Mohammed Rafii-El-Idrissi Benhnia and Victor Perez-Puyana
Polymers 2022, 14(2), 272; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14020272 - 10 Jan 2022
Cited by 12 | Viewed by 2527
Abstract
Hydrogels are considered good biomaterials for soft tissue regeneration. In this sense, collagen is the most used raw material to develop hydrogels, due to its high biocompatibility. However, its low mechanical resistance, thermal stability and pH instability have generated the need to look [...] Read more.
Hydrogels are considered good biomaterials for soft tissue regeneration. In this sense, collagen is the most used raw material to develop hydrogels, due to its high biocompatibility. However, its low mechanical resistance, thermal stability and pH instability have generated the need to look for alternatives to its use. In this sense, the combination of collagen with another raw material (i.e., polysaccharides) can improve the final properties of hydrogels. For this reason, the main objective of this work was the development of hydrogels based on collagen and chitosan. The mechanical, thermal and microstructural properties of the hydrogels formed with different ratios of collagen/chitosan (100/0, 75/25, 50/50, 25/75 and 0/100) were evaluated after being processed by two variants of a protocol consisting in two stages: a pH change towards pH 7 and a temperature drop towards 4 °C. The main results showed that depending on the protocol, the physicochemical and microstructural properties of the hybrid hydrogels were similar to the unitary system depending on the stage carried out in first place, obtaining FTIR peaks with similar intensity or a more porous structure when chitosan was first gelled, instead of collagen. As a conclusion, the synergy between collagen and chitosan improved the properties of the hydrogels, showing good thermomechanical properties and cell viability to be used as potential biomaterials for Tissue Engineering. Full article
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2021

Jump to: 2023, 2022, 2020, 2019

29 pages, 6956 KiB  
Article
Custom-Made Poly(urethane) Coatings Improve the Mechanical Properties of Bioactive Glass Scaffolds Designed for Bone Tissue Engineering
by Monica Boffito, Lucia Servello, Marcela Arango-Ospina, Serena Miglietta, Martina Tortorici, Susanna Sartori, Gianluca Ciardelli and Aldo R. Boccaccini
Polymers 2022, 14(1), 151; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14010151 - 31 Dec 2021
Cited by 1 | Viewed by 2031
Abstract
The replication method is a widely used technique to produce bioactive glass (BG) scaffolds mimicking trabecular bone. However, these scaffolds usually exhibit poor mechanical reliability and fast degradation, which can be improved by coating them with a polymer. In this work, we proposed [...] Read more.
The replication method is a widely used technique to produce bioactive glass (BG) scaffolds mimicking trabecular bone. However, these scaffolds usually exhibit poor mechanical reliability and fast degradation, which can be improved by coating them with a polymer. In this work, we proposed the use of custom-made poly(urethane)s (PURs) as coating materials for 45S5 Bioglass®-based scaffolds. In detail, BG scaffolds were dip-coated with two PURs differing in their soft segment (poly(ε-caprolactone) or poly(ε-caprolactone)/poly(ethylene glycol) 70/30 w/w) (PCL-PUR and PCL/PEG-PUR) or PCL (control). PUR-coated scaffolds exhibited biocompatibility, high porosity (ca. 91%), and improved mechanical properties compared to BG scaffolds (2–3 fold higher compressive strength). Interestingly, in the case of PCL-PUR, compressive strength significantly increased by coating BG scaffolds with an amount of polymer approx. 40% lower compared to PCL/PEG-PUR- and PCL-coated scaffolds. On the other hand, PEG presence within PCL/PEG-PUR resulted in a fast decrease in mechanical reliability in an aqueous environment. PURs represent promising coating materials for BG scaffolds, with the additional pros of being ad-hoc customized in their physico-chemical properties. Moreover, PUR-based coatings exhibited high adherence to the BG surface, probably because of the formation of hydrogen bonds between PUR N-H groups and BG surface functionalities, which were not formed when PCL was used. Full article
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17 pages, 7550 KiB  
Article
Extracellular Matrix Optimization for Enhanced Physiological Relevance in Hepatic Tissue-Chips
by Abdul Rahim Chethikkattuveli Salih, Kinam Hyun, Arun Asif, Afaque Manzoor Soomro, Hafiz Muhammad Umer Farooqi, Young Su Kim, Kyung Hwan Kim, Jae Wook Lee, Dongeun Huh and Kyung Hyun Choi
Polymers 2021, 13(17), 3016; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13173016 - 06 Sep 2021
Cited by 23 | Viewed by 3284
Abstract
The cellular microenvironment is influenced explicitly by the extracellular matrix (ECM), the main tissue support biomaterial, as a decisive factor for tissue growth patterns. The recent emergence of hepatic microphysiological systems (MPS) provide the basic physiological emulation of the human liver for drug [...] Read more.
The cellular microenvironment is influenced explicitly by the extracellular matrix (ECM), the main tissue support biomaterial, as a decisive factor for tissue growth patterns. The recent emergence of hepatic microphysiological systems (MPS) provide the basic physiological emulation of the human liver for drug screening. However, engineering microfluidic devices with standardized surface coatings of ECM may improve MPS-based organ-specific emulation for improved drug screening. The influence of surface coatings of different ECM types on tissue development needs to be optimized. Additionally, an intensity-based image processing tool and transepithelial electrical resistance (TEER) sensor may assist in the analysis of tissue formation capacity under the influence of different ECM types. The current study highlights the role of ECM coatings for improved tissue formation, implying the additional role of image processing and TEER sensors. We studied hepatic tissue formation under the influence of multiple concentrations of Matrigel, collagen, fibronectin, and poly-L-lysine. Based on experimental data, a mathematical model was developed, and ECM concentrations were validated for better tissue development. TEER sensor and image processing data were used to evaluate the development of a hepatic MPS for human liver physiology modeling. Image analysis data for tissue formation was further strengthened by metabolic quantification of albumin, urea, and cytochrome P450. Standardized ECM type for MPS may improve clinical relevance for modeling hepatic tissue microenvironment, and image processing possibly enhance the tissue analysis of the MPS. Full article
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21 pages, 5290 KiB  
Article
Evaluation of Composition Effects on the Physicochemical and Biological Properties of Polypeptide-Based Hydrogels for Potential Application in Wound Healing
by Johnel Giliomee, Lisa C. du Toit, Pradeep Kumar, Bert Klumperman and Yahya E. Choonara
Polymers 2021, 13(11), 1828; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13111828 - 31 May 2021
Cited by 5 | Viewed by 2561
Abstract
In this study, the effect of crosslinking and concentration on the properties of a new library of low-concentration poly(Lys60-ran-Ala40)-based hydrogels for potential application in wound healing was investigated in order to correlate the hydrogel composition with the [...] Read more.
In this study, the effect of crosslinking and concentration on the properties of a new library of low-concentration poly(Lys60-ran-Ala40)-based hydrogels for potential application in wound healing was investigated in order to correlate the hydrogel composition with the desired physicochemical and biofunctional properties to expand the assortment of poly-l-lysine (PLL)-based hydrogels suitable for wound healing. Controlled ring-opening polymerization (ROP) and precise hydrogel compositions were used to customize the physicochemical and biofunctional properties of a library of new hydrogels comprising poly(l-lysine-ran-l-alanine) and four-arm poly(ethylene glycol) (P(KA)/4-PEG). The chemical composition and degree of crosslinking via free amine quantification were analyzed for the P(KA)/4-PEG hydrogels. In addition, the rheological properties, pore morphology, swelling behavior and degradation time were characterized. Subsequently, in vitro cell studies for evaluation of the cytotoxicity and cell adhesion were performed. The 4 wt% 1:1 functional molar ratio hydrogel with P(KA) concentrations as low as 0.65 wt% demonstrated low cytotoxicity and desirable cell adhesion towards fibroblasts and thus displayed a desirable combination of properties for wound healing application. Full article
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14 pages, 2168 KiB  
Article
Olive Oil/Pluronic Oleogels for Skin Delivery of Quercetin: In Vitro Characterization and Ex Vivo Skin Permeability
by Mohammed Elmowafy, Arafa Musa, Taghreed S. Alnusaire, Khaled Shalaby, Maged M. A. Fouda, Ayman Salama, Mohammad M. Al-Sanea, Mohamed A. Abdelgawad, Mohammed Gamal and Shahinaze A. Fouad
Polymers 2021, 13(11), 1808; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13111808 - 31 May 2021
Cited by 16 | Viewed by 3392
Abstract
The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5–30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro [...] Read more.
The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5–30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro quercetin release and stability, and were compared with that of Pluronic F127 hydrogel. The selected formulation was characterized for its interaction possibility, ex vivo skin permeation and skin histological changes and safety. The particle sizes ranged from 345.3 ± 5.3 nm to 401.5 ± 2.8 nm, and possessed negative charges. The viscosities of the formulations were found in the range of 6367–4823 cps with inverse proportionality to olive oil percentage while the higher percentages showed higher quercetin release. Percentages of 25% and 30% olive oil showed instability pattern under the conditions of accelerated stability studies. Differential scanning calorimetry verified the existence of quercetin in micellar aggregation and the network in the case of hydrogel and oleogel respectively. Ex vivo skin permeation showed an improved skin permeation of quercetin when 20% olive oil containing oleogel was used. Skin histology after 10 days of application showed stratum corneum disruption and good safety profile. Based on these findings, the proposed oleogel containing 20% olive oil denotes a potential carrier for topical delivery of quercetin. Full article
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15 pages, 2281 KiB  
Article
Recovery of Gelatin from Bovine Skin with the Aid of Pepsin and Its Effects on the Characteristics of the Extracted Gelatin
by Tanbir Ahmad, Amin Ismail, Siti Aqlima Ahmad, Khalilah Abdul Khalil, Elmutaz Atta Awad, Muhammad Tayyab Akhtar and Awis Qurni Sazili
Polymers 2021, 13(10), 1554; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13101554 - 12 May 2021
Cited by 15 | Viewed by 4833
Abstract
Pepsin enzyme was used to pretreat the bovine skin at the rate of 5, 15, and 25 units of enzyme/g of skin to recover gelatin, and the recovered gelatins were referred to as Pe5, Pe15, and Pe25, respectively. The gelatin yield increased significantly [...] Read more.
Pepsin enzyme was used to pretreat the bovine skin at the rate of 5, 15, and 25 units of enzyme/g of skin to recover gelatin, and the recovered gelatins were referred to as Pe5, Pe15, and Pe25, respectively. The gelatin yield increased significantly (p < 0.05) from 18.17% for Pe5 to 24.67% for Pe25 as the level of pepsin increased, but the corresponding gel strength and viscosity decreased significantly (p < 0.05) from 215.49 to 56.06 g and 9.17 to 8.17 mPa·s for Pe5 and Pe25, respectively. β- and α1- and α2-chains were degraded entirely in all the gelatins samples as observed in protein pattern elaborated by gel electrophoresis. 1H nuclear magnetic resonance (1H NMR) analysis indicated the coiled structure of gelatin protein chains. The lowest amide III amplitude of Pe25 as found by Fourier transform infrared (FTIR) spectroscopy indicated that α-helix structure of protein chains were lost to more irregular coiled structure. Thus, it could be summarized that pepsin might be used at the lower level (5 units/g of wet skin) to extract gelatin from bovine skin with good functional properties and at higher level (15/25 units/g of wet skin) to obtain gelatin of industrial grade with high yield. Full article
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12 pages, 3104 KiB  
Article
Development and Evaluation of Rifampicin Loaded Alginate–Gelatin Biocomposite Microfibers
by Ameya Sharma, Vivek Puri, Pradeep Kumar, Inderbir Singh and Kampanart Huanbutta
Polymers 2021, 13(9), 1514; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13091514 - 08 May 2021
Cited by 12 | Viewed by 2438
Abstract
Various systematic phases such as inflammation, tissue proliferation, and phases of remodeling characterize the process of wound healing. The natural matrix system is suggested to maintain and escalate these phases, and for that, microfibers were fabricated employing naturally occurring polymers (biopolymers) such as [...] Read more.
Various systematic phases such as inflammation, tissue proliferation, and phases of remodeling characterize the process of wound healing. The natural matrix system is suggested to maintain and escalate these phases, and for that, microfibers were fabricated employing naturally occurring polymers (biopolymers) such as sodium alginate, gelatin and xanthan gum, and reinforcing material such as nanoclay was selected. The fabrication of fibers was executed with the aid of extrusion-gelation method. Rifampicin, an antibiotic, has been incorporated into a biopolymeric solution. RF1, RF2, RF3, RF4 and RF5 were coded as various formulation batches of microfibers. The microfibers were further characterized by different techniques such as SEM, DSC, XRD, and FTIR. Mechanical properties and physical evaluations such as entrapment efficiency, water uptake and in vitro release were also carried out to explain the comparative understanding of the formulation developed. The antimicrobial activity and whole blood clotting of fabricated fibers were additionally executed, hence they showed significant results, having excellent antimicrobial properties; they could be prominent carriers for wound healing applications. Full article
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17 pages, 3783 KiB  
Article
Development and Characterization of Cellulose/Iron Acetate Nanofibers for Bone Tissue Engineering Applications
by Hamouda M. Mousa, Kamal Hany Hussein, Mostafa M. Sayed, Mohamed K. Abd El-Rahman and Heung-Myong Woo
Polymers 2021, 13(8), 1339; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13081339 - 20 Apr 2021
Cited by 25 | Viewed by 3091
Abstract
In tissue engineering, design of biomaterial with a micro/nano structure is an essential step to mimic extracellular matrix (ECM) and to enhance biomineralization as well as cell biocompatibility. Composite polymeric nanofiber with iron particles/ions has an important role in biomineralization and collagen synthesis [...] Read more.
In tissue engineering, design of biomaterial with a micro/nano structure is an essential step to mimic extracellular matrix (ECM) and to enhance biomineralization as well as cell biocompatibility. Composite polymeric nanofiber with iron particles/ions has an important role in biomineralization and collagen synthesis for bone tissue engineering. Herein, we report development of polymeric cellulose acetate (CA) nanofibers (17 wt.%) and traces of iron acetates salt (0.5 wt.%) within a polymeric solution to form electrospinning nanofibers mats with iron nanoparticles for bone tissue engineering applications. The resulting mats were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The resulted morphology indicated that the average diameter of CA decreased after addition of iron from (395 ± 30) to (266 ± 19) nm and had dense fiber distributions that match those of native ECM. Moreover, addition of iron acetate to CA solution resulted in mats that are thermally stable. The initial decomposition temperature was 300 °C of CA/Fe mat > 270 °C of pure CA. Furthermore, a superior apatite formation resulted in a biomineralization test after 3 days of immersion in stimulated environmental condition. In vitro cell culture experiments demonstrated that the CA/Fe mat was biocompatible to human fetal-osteoblast cells (hFOB) with the ability to support the cell attachment and proliferation. These findings suggest that doping traces of iron acetate has a promising role in composite mats designed for bone tissue engineering as simple and economically nanoscale materials. Furthermore, these biomaterials can be used in a potential future application such as drug delivery, cancer treatment, and antibacterial materials. Full article
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14 pages, 1156 KiB  
Review
Multifunctional Hydrogel Nanocomposites for Biomedical Applications
by Emma Barrett-Catton, Murial L. Ross and Prashanth Asuri
Polymers 2021, 13(6), 856; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13060856 - 11 Mar 2021
Cited by 46 | Viewed by 6401
Abstract
Hydrogels are used for various biomedical applications due to their biocompatibility, capacity to mimic the extracellular matrix, and ability to encapsulate and deliver cells and therapeutics. However, traditional hydrogels have a few shortcomings, especially regarding their physical properties, thereby limiting their broad applicability. [...] Read more.
Hydrogels are used for various biomedical applications due to their biocompatibility, capacity to mimic the extracellular matrix, and ability to encapsulate and deliver cells and therapeutics. However, traditional hydrogels have a few shortcomings, especially regarding their physical properties, thereby limiting their broad applicability. Recently, researchers have investigated the incorporation of nanoparticles (NPs) into hydrogels to improve and add to the physical and biochemical properties of hydrogels. This brief review focuses on papers that describe the use of nanoparticles to improve more than one property of hydrogels. Such multifunctional hydrogel nanocomposites have enhanced potential for various applications including tissue engineering, drug delivery, wound healing, bioprinting, and biowearable devices. Full article
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20 pages, 1626 KiB  
Review
Molecular Imprinting Strategies for Tissue Engineering Applications: A Review
by Amedeo Franco Bonatti, Carmelo De Maria and Giovanni Vozzi
Polymers 2021, 13(4), 548; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13040548 - 12 Feb 2021
Cited by 14 | Viewed by 2580
Abstract
Tissue Engineering (TE) represents a promising solution to fabricate engineered constructs able to restore tissue damage after implantation. In the classic TE approach, biomaterials are used alongside growth factors to create a scaffolding structure that supports cells during the construct maturation. A current [...] Read more.
Tissue Engineering (TE) represents a promising solution to fabricate engineered constructs able to restore tissue damage after implantation. In the classic TE approach, biomaterials are used alongside growth factors to create a scaffolding structure that supports cells during the construct maturation. A current challenge in TE is the creation of engineered constructs able to mimic the complex microenvironment found in the natural tissue, so as to promote and guide cell migration, proliferation, and differentiation. In this context, the introduction inside the scaffold of molecularly imprinted polymers (MIPs)—synthetic receptors able to reversibly bind to biomolecules—holds great promise to enhance the scaffold-cell interaction. In this review, we analyze the main strategies that have been used for MIP design and fabrication with a particular focus on biomedical research. Furthermore, to highlight the potential of MIPs for scaffold-based TE, we present recent examples on how MIPs have been used in TE to introduce biophysical cues as well as for drug delivery and sequestering. Full article
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2020

Jump to: 2023, 2022, 2021, 2019

9 pages, 1861 KiB  
Article
Impact of Ergothioneine, Hercynine, and Histidine on Oxidative Degradation of Hyaluronan and Wound Healing
by Katarina Valachova, Karol Svik, Csaba Biro, Maurice N. Collins, Rastislav Jurcik, Lubomir Ondruska and Ladislav Soltes
Polymers 2021, 13(1), 95; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13010095 - 29 Dec 2020
Cited by 50 | Viewed by 4141
Abstract
A high-molecular weight hyaluronan is oxidatively degraded by Cu(II) ions and ascorbate—the so called Weissberger biogenic oxidative system—which is one of the most potent generators of reactive oxygen species, namely OH radicals. Ergothioneine, hercynine, or histidine were loaded into chitosan/hyaluronan composite membranes [...] Read more.
A high-molecular weight hyaluronan is oxidatively degraded by Cu(II) ions and ascorbate—the so called Weissberger biogenic oxidative system—which is one of the most potent generators of reactive oxygen species, namely OH radicals. Ergothioneine, hercynine, or histidine were loaded into chitosan/hyaluronan composite membranes to examine their effect on skin wound healing in ischemic rabbits. We also explored the ability of ergothioneine, hercynine, or histidine to inhibit hyaluronan degradation. Rotational viscometry showed that ergothioneine decreased the degree of hyaluronan radical degradation in a dose-dependent manner. While histidine was shown to be potent in scavenging OH radicals, however, hercynine was ineffective. In vivo results showed that the addition of each investigated agent to chitosan/hyaluronan membranes contributed to a more potent treatment of ischemic skin wounds in rabbits compared to untreated animals and animals treated only with chitosan/hyaluronan membranes. Full article
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30 pages, 11710 KiB  
Review
Current Advances in 3D Bioprinting Technology and Its Applications for Tissue Engineering
by JunJie Yu, Su A Park, Wan Doo Kim, Taeho Ha, Yuan-Zhu Xin, JunHee Lee and Donghyun Lee
Polymers 2020, 12(12), 2958; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12122958 - 11 Dec 2020
Cited by 48 | Viewed by 8394
Abstract
Three-dimensional (3D) bioprinting technology has emerged as a powerful biofabrication platform for tissue engineering because of its ability to engineer living cells and biomaterial-based 3D objects. Over the last few decades, droplet-based, extrusion-based, and laser-assisted bioprinters have been developed to fulfill certain requirements [...] Read more.
Three-dimensional (3D) bioprinting technology has emerged as a powerful biofabrication platform for tissue engineering because of its ability to engineer living cells and biomaterial-based 3D objects. Over the last few decades, droplet-based, extrusion-based, and laser-assisted bioprinters have been developed to fulfill certain requirements in terms of resolution, cell viability, cell density, etc. Simultaneously, various bio-inks based on natural–synthetic biomaterials have been developed and applied for successful tissue regeneration. To engineer more realistic artificial tissues/organs, mixtures of bio-inks with various recipes have also been developed. Taken together, this review describes the fundamental characteristics of the existing bioprinters and bio-inks that have been currently developed, followed by their advantages and disadvantages. Finally, various tissue engineering applications using 3D bioprinting are briefly introduced. Full article
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18 pages, 3097 KiB  
Article
Yerba Mate Extract in Microfibrillated Cellulose and Corn Starch Films as a Potential Wound Healing Bandage
by Meysam Aliabadi, Bor Shin Chee, Mailson Matos, Yvonne J. Cortese, Michael J. D. Nugent, Tielidy A. M. de Lima, Washington L. E. Magalhães and Gabriel Goetten de Lima
Polymers 2020, 12(12), 2807; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12122807 - 27 Nov 2020
Cited by 13 | Viewed by 2706
Abstract
Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has [...] Read more.
Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has been reported to possess a high quantity of caffeoylquinic acids that may be beneficial for other applications instead of its conventional use as a hot beverage. Therefore, we investigate the effect of blending yerba mate extract during and after defibrillation of Eucalyptus sp. bleached kraft paper by ultrafine grinding. Blending the extract during defibrillation increased the mechanical and thermal properties, besides being able to use the whole extract. Afterwards, this material was also investigated with high content loadings of starch and glycerine. The results present that yerba mate extract increases film resistance, and the defibrillated cellulose is able to protect the bioactive compounds from the extract. Additionally, the films present antibacterial activity against two known pathogens S. aureus and E. coli, with high antioxidant activity and increased cell proliferation. This was attributed to the bioactive compounds that presented faster in vitro wound healing, suggesting that microfibrillated cellulose (MFC) films containing extract of yerba mate can be a potential alternative as wound healing bandages. Full article
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14 pages, 1623 KiB  
Article
A Novel Microfiber Wipe for Delivery of Active Substances to Human Skin: Clinical Proof of Concept
by Martin Kaegi, Christian Adlhart, Markus Lehmann, Marius Risch, Werner Wessling and Peter Klaffenbach
Polymers 2020, 12(11), 2715; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12112715 - 17 Nov 2020
Viewed by 1943
Abstract
A novel technology for the delivery of active substances to the skin based on microfibers loaded with dried active substances was developed. The objective of this work was to demonstrate deposition of the active substances on the skin including concurrent cleansing properties of [...] Read more.
A novel technology for the delivery of active substances to the skin based on microfibers loaded with dried active substances was developed. The objective of this work was to demonstrate deposition of the active substances on the skin including concurrent cleansing properties of the wipe. As model active substance to measure deposition capacity Niacinamide was used and as parameter to measure cleansing capacities of the wipe squalene uptake was measured. Wipes loaded with niacinamide were used in the face and the forearm of 25 subjects. By means of Raman spectrometry the deposited niacinamide was analyzed before and after application. Wipes used on the face were analyzed for squalene to assess skin cleansing properties and for residual niacinamide. Forearm analysis including placebo and verum on left and right arm respectively was performed to rule out changes of the skin through application of the tissue. Measured amounts of niacinamide from face application demonstrate statistically significant results in the study population. Analysis of the wipes used show a liberation of 28.3% of niacinamide from the wipes and an uptake of 1.7 mg squalene per wipe. Results from forearm application show statistically significant differences (p < 0.05) between placebo and active for the complete study population. Sub group analyses are significant for both gender and ethnicity for face and forearm analysis respectively. Results clearly demonstrate deposition of niacinamide on the skin and the cleansing properties of the wipe. The institutional review board approved this prospective study. Full article
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10 pages, 3150 KiB  
Article
Poly(ε-Caprolactone)/Poly(Glycerol Sebacate) Composite Nanofibers Incorporating Hydroxyapatite Nanoparticles and Simvastatin for Bone Tissue Regeneration and Drug Delivery Applications
by Abdelrahman I. Rezk, Kyung-Suk Kim and Cheol Sang Kim
Polymers 2020, 12(11), 2667; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12112667 - 12 Nov 2020
Cited by 28 | Viewed by 3257
Abstract
Herein, we report a drug eluting scaffold composed of a composite nanofibers of poly(ε-caprolactone) (PCL) and poly(glycerol sebacate) (PGS) loaded with Hydroxyapatite nanoparticles (HANPs) and simvastatin (SIM) mimicking the bone extracellular matrix (ECM) to improve bone cell proliferation and regeneration process. Indeed, the [...] Read more.
Herein, we report a drug eluting scaffold composed of a composite nanofibers of poly(ε-caprolactone) (PCL) and poly(glycerol sebacate) (PGS) loaded with Hydroxyapatite nanoparticles (HANPs) and simvastatin (SIM) mimicking the bone extracellular matrix (ECM) to improve bone cell proliferation and regeneration process. Indeed, the addition of PGS results in a slight increase in the average fiber diameter compared to PCL. However, the presence of HANPs in the composite nanofibers induced a greater fiber diameter distribution, without significantly changing the average fiber diameter. The in vitro drug release result revealed that the sustained release of SIM from the composite nanofiber obeying the Korsemeyer–Peppas and Kpocha models revealing a non-Fickian diffusion mechanism and the release mechanism follows diffusion rather than polymer erosion. Biomineralization assessment of the nanofibers was carried out in simulated body fluid (SBF). SEM and EDS analysis confirmed nucleation of the hydroxyapatite layer on the surface of the composite nanofibers mimicking the natural apatite layer. Moreover, in vitro studies revealed that the PCL-PGS-HA displayed better cell proliferation and adhesion compared to the control sample, hence improving the regeneration process. This suggests that the fabricated PCL-PGS-HA could be a promising future scaffold for control drug delivery and bone tissue regeneration application. Full article
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23 pages, 1148 KiB  
Review
Natural and Synthetic Biomaterials for Engineering Multicellular Tumor Spheroids
by Advika Kamatar, Gokhan Gunay and Handan Acar
Polymers 2020, 12(11), 2506; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12112506 - 28 Oct 2020
Cited by 54 | Viewed by 9897
Abstract
The lack of in vitro models that represent the native tumor microenvironment is a significant challenge for cancer research. Two-dimensional (2D) monolayer culture has long been the standard for in vitro cell-based studies. However, differences between 2D culture and the in vivo environment [...] Read more.
The lack of in vitro models that represent the native tumor microenvironment is a significant challenge for cancer research. Two-dimensional (2D) monolayer culture has long been the standard for in vitro cell-based studies. However, differences between 2D culture and the in vivo environment have led to poor translation of cancer research from in vitro to in vivo models, slowing the progress of the field. Recent advances in three-dimensional (3D) culture have improved the ability of in vitro culture to replicate in vivo conditions. Although 3D cultures still cannot achieve the complexity of the in vivo environment, they can still better replicate the cell–cell and cell–matrix interactions of solid tumors. Multicellular tumor spheroids (MCTS) are three-dimensional (3D) clusters of cells with tumor-like features such as oxygen gradients and drug resistance, and represent an important translational tool for cancer research. Accordingly, natural and synthetic polymers, including collagen, hyaluronic acid, Matrigel®, polyethylene glycol (PEG), alginate and chitosan, have been used to form and study MCTS for improved clinical translatability. This review evaluates the current state of biomaterial-based MCTS formation, including advantages and disadvantages of the different biomaterials and their recent applications to the field of cancer research, with a focus on the past five years. Full article
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16 pages, 5605 KiB  
Article
Morphological Changes in Astrocytes by Self-Oxidation of Dopamine to Polydopamine and Quantification of Dopamine through Multivariate Regression Analysis of Polydopamine Images
by Anik Karan, Elnaz Khezerlou, Farnaz Rezaei, Leon Iasemidis and Mark A. DeCoster
Polymers 2020, 12(11), 2483; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12112483 - 26 Oct 2020
Cited by 6 | Viewed by 2376
Abstract
Astrocytes, also known as astroglia, are important cells for the structural support of neurons as well as for biochemical balance in the central nervous system (CNS). In this study, the polymerization of dopamine (DA) to polydopamine (PDA) and its effect on astrocytes was [...] Read more.
Astrocytes, also known as astroglia, are important cells for the structural support of neurons as well as for biochemical balance in the central nervous system (CNS). In this study, the polymerization of dopamine (DA) to polydopamine (PDA) and its effect on astrocytes was investigated. The polymerization of DA, being directly proportional to the DA concentration, raises the prospect of detecting DA concentration from PDA optically using image-processing techniques. It was found here that DA, a naturally occurring neurotransmitter, significantly altered astrocyte cell number, morphology, and metabolism, compared to astrocytes in the absence of DA. Along with these effects on astrocytes, the polymerization of DA to PDA was tracked optically in the same cell culture wells. This polymerization process led to a unique methodology based on multivariate regression analysis that quantified the concentration of DA from optical images of astrocyte cell culture media. Therefore, this developed methodology, combined with conventional imaging equipment, could be used in place of high-end and expensive analytical chemistry instruments, such as spectrophotometry, mass spectrometry, and fluorescence techniques, for quantification of the concentration of DA after polymerization to PDA under in vitro and potentially in vivo conditions. Full article
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8 pages, 1689 KiB  
Article
Enhanced Bioactivity of Micropatterned Hydroxyapatite Embedded Poly(L-lactic) Acid for a Load-Bearing Implant
by Sae-Mi Kim, In-Gu Kang, Kwang-Hee Cheon, Tae-Sik Jang, Hyoun-Ee Kim, Hyun-Do Jung and Min-Ho Kang
Polymers 2020, 12(10), 2390; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102390 - 17 Oct 2020
Cited by 8 | Viewed by 2121
Abstract
Poly(L-lactic) acid (PLLA) is among the most promising polymers for bone fixation, repair, and tissue engineering due to its biodegradability and relatively good mechanical strength. Despite these beneficial characteristics, its poor bioactivity often requires incorporation of bioactive ceramic materials. A bioresorbable composite made [...] Read more.
Poly(L-lactic) acid (PLLA) is among the most promising polymers for bone fixation, repair, and tissue engineering due to its biodegradability and relatively good mechanical strength. Despite these beneficial characteristics, its poor bioactivity often requires incorporation of bioactive ceramic materials. A bioresorbable composite made of PLLA and hydroxyapatite (HA) may improve biocompatibility but typically causes deterioration in mechanical properties, and bioactive coatings inevitably carry a risk of coating delamination. Therefore, in this study, we embedded micropatterned HA on the surface of PLLA to improve bioactivity while eliminating the risk of HA delamination. An HA pattern was successfully embedded in a PLLA matrix without degeneration of the matrix’s mechanical properties, thanks to a transfer technique involving conversion of Mg to HA. Furthermore, patterned HA/PLLA’s biological response outperformed that of pure PLLA. These results confirm patterned HA/PLLA as a candidate for wide acceptance in biodegradable load-bearing implant applications. Full article
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15 pages, 4079 KiB  
Article
The Rheological Studies on Poly(vinyl) Alcohol-Based Hydrogel Magnetorheological Plastomer
by Norhiwani Mohd Hapipi, Saiful Amri Mazlan, U. Ubaidillah, Koji Homma, Siti Aishah Abdul Aziz, Nur Azmah Nordin, Irfan Bahiuddin and Nurhazimah Nazmi
Polymers 2020, 12(10), 2332; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102332 - 13 Oct 2020
Cited by 9 | Viewed by 2660
Abstract
The freezing–thawing method has been commonly used in the preparation of polyvinyl alcohol hydrogel magnetorheological plastomer (PVA HMRP). However, this method is complex and time consuming as it requires high energy consumption and precise temperature control. In this study, PVA HMRP was prepared [...] Read more.
The freezing–thawing method has been commonly used in the preparation of polyvinyl alcohol hydrogel magnetorheological plastomer (PVA HMRP). However, this method is complex and time consuming as it requires high energy consumption and precise temperature control. In this study, PVA HMRP was prepared using a chemically crosslinked method, where borax is used as crosslinking agent capable of changing the rheological properties of the material. Three samples of PVA HMRP with various contents of carbonyl iron particles (CIPs) (50, 60, and 70 wt.%) were used to investigate their rheological properties in both steady shear and dynamic oscillation modes. Results showed the occurrence of shear thickening behaviour at low shear rate (γ > 1 s−1), where the viscosity increased with the increased of shear rate. Moreover, the storage modulus of the samples also increased increasing the oscillation frequency from 0.1 to 100 Hz. Interestingly, the samples with 50, 60 70 wt.% of CIPs produced large relative magnetorheological (MR) effects at 4916%, 6165%, and 10,794%, respectively. Therefore, the inclusion of borax to the PVA HMRP can offer solutions for a wide range of applications, especially in artificial muscle, soft actuators, and biomedical sensors. Full article
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12 pages, 5173 KiB  
Article
A Collagen-Based Scaffold for Promoting Neural Plasticity in a Rat Model of Spinal Cord Injury
by Jue-Zong Yeh, Ding-Han Wang, Juin-Hong Cherng, Yi-Wen Wang, Gang-Yi Fan, Nien-Hsien Liou, Jiang-Chuan Liu and Chung-Hsing Chou
Polymers 2020, 12(10), 2245; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102245 - 29 Sep 2020
Cited by 12 | Viewed by 3407
Abstract
In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate [...] Read more.
In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate environment in an SCI rat model and determined whether neural plasticity can be manipulated using this approach. We used four experimental groups, as follows: SCI-collagen scaffold, SCI control, normal spinal cord-collagen scaffold, and normal control. The collagen scaffold showed excellent in vitro and in vivo biocompatibility. Immunofluorescence staining revealed increased expression of neurofilament and fibronectin and reduced expression of glial fibrillary acidic protein and anti-chondroitin sulfate in the collagen scaffold-treated SCI rats at 1 and 4 weeks post-implantation compared with that in untreated SCI control. This indicates that the collagen scaffold implantation promoted neuronal survival and axonal growth within the injured site and prevented glial scar formation by controlling astrocyte production for their normal functioning. Our study highlights the feasibility of using the collagen scaffold in SCI repair. The collagen scaffold was found to exert beneficial effects on neuronal activity and may help in manipulating synaptic plasticity, implying its great potential for clinical application in SCI. Full article
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36 pages, 4245 KiB  
Review
Fish Collagen: Extraction, Characterization, and Applications for Biomaterials Engineering
by Hafez Jafari, Alberto Lista, Manuela Mafosso Siekapen, Pejman Ghaffari-Bohlouli, Lei Nie, Houman Alimoradi and Amin Shavandi
Polymers 2020, 12(10), 2230; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102230 - 28 Sep 2020
Cited by 189 | Viewed by 26775
Abstract
The utilization of marine-based collagen is growing fast due to its unique properties in comparison with mammalian-based collagen such as no risk of transmitting diseases, a lack of religious constraints, a cost-effective process, low molecular weight, biocompatibility, and its easy absorption by the [...] Read more.
The utilization of marine-based collagen is growing fast due to its unique properties in comparison with mammalian-based collagen such as no risk of transmitting diseases, a lack of religious constraints, a cost-effective process, low molecular weight, biocompatibility, and its easy absorption by the human body. This article presents an overview of the recent studies from 2014 to 2020 conducted on collagen extraction from marine-based materials, in particular fish by-products. The fish collagen structure, extraction methods, characterization, and biomedical applications are presented. More specifically, acetic acid and deep eutectic solvent (DES) extraction methods for marine collagen isolation are described and compared. In addition, the effect of the extraction parameters (temperature, acid concentration, extraction time, solid-to-liquid ratio) on the yield of collagen is investigated. Moreover, biomaterials engineering and therapeutic applications of marine collagen have been summarized. Full article
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16 pages, 9131 KiB  
Article
Fabrication of a Polycaprolactone/Alginate Bipartite Hybrid Scaffold for Osteochondral Tissue Using a Three-Dimensional Bioprinting System
by JunJie Yu, SuJeong Lee, Sunkyung Choi, Kee K. Kim, Bokyeong Ryu, C-Yoon Kim, Cho-Rok Jung, Byoung-Hyun Min, Yuan-Zhu Xin, Su A Park, Wandoo Kim, Donghyun Lee and JunHee Lee
Polymers 2020, 12(10), 2203; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12102203 - 25 Sep 2020
Cited by 17 | Viewed by 3492
Abstract
Osteochondral defects, including damage to both the articular cartilage and the subchondral bone, are challenging to repair. Although many technological advancements have been made in recent years, there are technical difficulties in the engineering of cartilage and bone layers, simultaneously. Moreover, there is [...] Read more.
Osteochondral defects, including damage to both the articular cartilage and the subchondral bone, are challenging to repair. Although many technological advancements have been made in recent years, there are technical difficulties in the engineering of cartilage and bone layers, simultaneously. Moreover, there is a great need for a valuable in vitro platform enabling the assessment of osteochondral tissues to reduce pre-operative risk. Three-dimensional (3D) bioprinting systems may be a promising approach for fabricating human tissues and organs. Here, we aimed to develop a polycaprolactone (PCL)/alginate bipartite hybrid scaffold using a multihead 3D bioprinting system. The hybrid scaffold was composed of PCL, which could improve the mechanical properties of the construct, and alginate, encapsulating progenitor cells that could differentiate into cartilage and bone. To differentiate the bipartite hybrid scaffold into osteochondral tissue, a polydimethylsiloxane coculture system for osteochondral tissue (PCSOT) was designed and developed. Based on evaluation of the biological performance of the novel hybrid scaffold, the PCL/alginate bipartite scaffold was successfully fabricated; importantly, our findings suggest that this PCSOT system may be applicable as an in vitro platform for osteochondral tissue engineering. Full article
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15 pages, 41306 KiB  
Article
Characterization of Bone Marrow and Wharton’s Jelly Mesenchymal Stromal Cells Response on Multilayer Braided Silk and Silk/PLCL Scaffolds for Ligament Tissue Engineering
by Xing Liu, Adrien Baldit, Emilie de Brosses, Frédéric Velard, Ghislaine Cauchois, Yun Chen, Xiong Wang, Natalia de Isla and Cédric Laurent
Polymers 2020, 12(9), 2163; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12092163 - 22 Sep 2020
Cited by 8 | Viewed by 2802
Abstract
(1) Background: A suitable scaffold with adapted mechanical and biological properties for ligament tissue engineering is still missing. (2) Methods: Different scaffold configurations were characterized in terms of morphology and a mechanical response, and their interactions with two types of stem cells (Wharton’s [...] Read more.
(1) Background: A suitable scaffold with adapted mechanical and biological properties for ligament tissue engineering is still missing. (2) Methods: Different scaffold configurations were characterized in terms of morphology and a mechanical response, and their interactions with two types of stem cells (Wharton’s jelly mesenchymal stromal cells (WJ-MSCs) and bone marrow mesenchymal stromal cells (BM-MSCs)) were assessed. The scaffold configurations consisted of multilayer braids with various number of silk layers (n = 1, 2, 3), and a novel composite scaffold made of a layer of copoly(lactic acid-co-(e-caprolactone)) (PLCL) embedded between two layers of silk. (3) Results: The insertion of a PLCL layer resulted in a higher porosity and better mechanical behavior compared with pure silk scaffold. The metabolic activities of both WJ-MSCs and BM-MSCs increased from day 1 to day 7 except for the three-layer silk scaffold (S3), probably due to its lower porosity. Collagen I (Col I), collagen III (Col III) and tenascin-c (TNC) were expressed by both MSCs on all scaffolds, and expression of Col I was higher than Col III and TNC. (4) Conclusions: the silk/PLCL composite scaffolds constituted the most suitable tested configuration to support MSCs migration, proliferation and tissue synthesis towards ligament tissue engineering. Full article
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11 pages, 8252 KiB  
Article
Functional Polylactide Blend Films for Controlling Mesenchymal Stem Cell Behaviour
by Yuliya Nashchekina, Pavel Nikonov, Alexey Nashchekin and Natalya Mikhailova
Polymers 2020, 12(9), 1969; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12091969 - 30 Aug 2020
Cited by 6 | Viewed by 2162
Abstract
Polymer blending is a suitable physical modification method to create novel properties of different polymers. Blending polylactic acid (PLA) and polyethylene glycol (PEG) produces materials with a wide range of properties. This study was the first to investigate the effect of different isomeric [...] Read more.
Polymer blending is a suitable physical modification method to create novel properties of different polymers. Blending polylactic acid (PLA) and polyethylene glycol (PEG) produces materials with a wide range of properties. This study was the first to investigate the effect of different isomeric forms of PLA and PEG with terminal amino groups to obtain biocompatible films for human mesenchymal stem cell cultivation. It has been shown by scanning electron microscopy that the surface topology changes to the greatest extent when using films obtained on the basis of poly(d,l-lactide) and PEG with high molecular weights (15,000 g/mol). In order to obtain thin films and rapid evaporation of the solvent, PEG is mixed with PLA and does not form a separate phase and is not further washed out during the incubation in water. The presence of PEG with terminal hydroxyl and amino groups in blend films after incubation in water was proven using Fourier transform infrared (FTIR) spectroscopy. Results of fluorescence microscopy demonstrated that blend films formed on PLA and polyethylene glycol diamine (PEG-NH2) are more suitable for cell spreading and focal contact formation compared to cells cultured on the surface of pure PLA films or films made from PLA and PEG. Full article
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31 pages, 9694 KiB  
Review
Layer-By-Layer Assemblies of Biopolymers: Build-Up, Mechanical Stability and Molecular Dynamics
by Jack Campbell and Anna S. Vikulina
Polymers 2020, 12(9), 1949; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12091949 - 28 Aug 2020
Cited by 37 | Viewed by 5183
Abstract
Rapid development of versatile layer-by-layer technology has resulted in important breakthroughs in the understanding of the nature of molecular interactions in multilayer assemblies made of polyelectrolytes. Nowadays, polyelectrolyte multilayers (PEM) are considered to be non-equilibrium and highly dynamic structures. High interest in biomedical [...] Read more.
Rapid development of versatile layer-by-layer technology has resulted in important breakthroughs in the understanding of the nature of molecular interactions in multilayer assemblies made of polyelectrolytes. Nowadays, polyelectrolyte multilayers (PEM) are considered to be non-equilibrium and highly dynamic structures. High interest in biomedical applications of PEMs has attracted attention to PEMs made of biopolymers. Recent studies suggest that biopolymer dynamics determines the fate and the properties of such PEMs; however, deciphering, predicting and controlling the dynamics of polymers remains a challenge. This review brings together the up-to-date knowledge of the role of molecular dynamics in multilayers assembled from biopolymers. We discuss how molecular dynamics determines the properties of these PEMs from the nano to the macro scale, focusing on its role in PEM formation and non-enzymatic degradation. We summarize the factors allowing the control of molecular dynamics within PEMs, and therefore to tailor polymer multilayers on demand. Full article
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19 pages, 4065 KiB  
Article
Micro-Clotting of Platelet-Rich Plasma Upon Loading in Hydrogel Microspheres Leads to Prolonged Protein Release and Slower Microsphere Degradation
by Miran Hannah Choi, Alexandra Blanco, Samuel Stealey, Xin Duan, Natasha Case, Scott Allen Sell, Muhammad Farooq Rai and Silviya Petrova Zustiak
Polymers 2020, 12(8), 1712; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12081712 - 30 Jul 2020
Cited by 16 | Viewed by 3955
Abstract
Platelet-rich plasma (PRP) is an autologous blood product that contains a variety of growth factors (GFs) that are released upon platelet activation. Despite some therapeutic potential of PRP in vitro, in vivo data are not convincing. Bolus injection of PRP is cleared rapidly [...] Read more.
Platelet-rich plasma (PRP) is an autologous blood product that contains a variety of growth factors (GFs) that are released upon platelet activation. Despite some therapeutic potential of PRP in vitro, in vivo data are not convincing. Bolus injection of PRP is cleared rapidly from the body diminishing its therapeutic efficacy. This highlights a need for a delivery vehicle for a sustained release of PRP to improve its therapeutic effect. In this study, we used microfluidics to fabricate biodegradable PRP-loaded polyethylene glycol (PEG) microspheres. PRP was incorporated into the microspheres as a lyophilized PRP powder either as is (powder PRP) or first solubilized and pre-clotted to remove clots (liquid PRP). A high PRP loading of 10% w/v was achieved for both PRP preparations. We characterized the properties of the resulting PRP-loaded PEG microspheres including swelling, modulus, degradation, and protein release as a function of PRP loading and preparation. Overall, loading powder PRP into the PEG microspheres significantly affected the properties of microspheres, with the most pronounced effect noted in degradation. We further determined that microsphere degradation in the presence of powder PRP was affected by platelet aggregation and clotting. Platelet aggregation did not prevent but prolonged sustained PRP release from the microspheres. The delivery system developed and characterized herein could be useful for the loading and releasing of PRP to promote tissue regeneration and wound healing or to suppress tissue degeneration in osteoarthritis, and intervertebral disc degeneration. Full article
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21 pages, 1667 KiB  
Review
Polymer-Based Scaffolds for Soft-Tissue Engineering
by Victor Perez-Puyana, Mercedes Jiménez-Rosado, Alberto Romero and Antonio Guerrero
Polymers 2020, 12(7), 1566; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12071566 - 15 Jul 2020
Cited by 41 | Viewed by 4820
Abstract
Biomaterials have been used since ancient times. However, it was not until the late 1960s when their development prospered, increasing the research on them. In recent years, the study of biomaterials has focused mainly on tissue regeneration, requiring a biomaterial that can support [...] Read more.
Biomaterials have been used since ancient times. However, it was not until the late 1960s when their development prospered, increasing the research on them. In recent years, the study of biomaterials has focused mainly on tissue regeneration, requiring a biomaterial that can support cells during their growth and fulfill the function of the replaced tissue until its regeneration. These materials, called scaffolds, have been developed with a wide variety of materials and processes, with the polymer ones being the most advanced. For this reason, the need arises for a review that compiles the techniques most used in the development of polymer-based scaffolds. This review has focused on three of the most used techniques: freeze-drying, electrospinning and 3D printing, focusing on current and future trends. In addition, the advantages and disadvantages of each of them have been compared. Full article
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19 pages, 5123 KiB  
Article
Investigations on the Mechanical Properties of Glass Fiber/Sisal Fiber/Chitosan Reinforced Hybrid Polymer Sandwich Composite Scaffolds for Bone Fracture Fixation Applications
by Soundhar Arumugam, Jayakrishna Kandasamy, Ain Umaira Md Shah, Mohamed Thariq Hameed Sultan, Syafiqah Nur Azrie Safri, Mohd Shukry Abdul Majid, Adi Azriff Basri and Faizal Mustapha
Polymers 2020, 12(7), 1501; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12071501 - 06 Jul 2020
Cited by 35 | Viewed by 4329
Abstract
This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications. The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as [...] Read more.
This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications. The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as the inner layers. The composite plate resembles the human bone structure (spongy internal cancellous matrix and rigid external cortical). The mechanical properties of the prepared hybrid sandwich composites samples were evaluated using tensile, flexural, micro hardness, and compression tests. The scanning electron microscopic (SEM) images were studied to analyze the failure mechanism of these composite samples. Besides, contact angle (CA) and water absorption tests were conducted using the sessile drop method to examine the wettability properties of the SF/CTS/epoxy and GF/SF/CTS/epoxy composites. Additionally, the porosity of the GF/SF/CTS composite scaffold samples were determined by using the ethanol infiltration method. The mechanical test results show that the GF/SF/CTS hybrid composites exhibit the bending strength of 343 MPa, ultimate tensile strength of 146 MPa, and compressive strength of 380 MPa with higher Young’s modulus in the bending tests (21.56 GPa) compared to the tensile (6646 MPa) and compressive modulus (2046 MPa). Wettability study results reveal that the GF/SF/CTS composite scaffolds were hydrophobic (CA = 92.41° ± 1.71°) with less water absorption of 3.436% compared to the SF/CTS composites (6.953%). The SF/CTS composites show a hydrophilic character (CA = 54.28° ± 3.06°). The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future. Full article
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14 pages, 4375 KiB  
Article
Sol–Gel Synthesis, Physico-Chemical and Biological Characterization of Cerium Oxide/Polyallylamine Nanoparticles
by Motaharesadat Hosseini, Issa Amjadi, Mohammad Mohajeri and Masoud Mozafari
Polymers 2020, 12(7), 1444; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12071444 - 28 Jun 2020
Cited by 25 | Viewed by 3721
Abstract
Cerium oxide nanoparticles (CeO2-NPs) have great applications in different industries, including nanomedicine. However, some studies report CeO2-NPs-related toxicity issues that limit their usage and efficiency. In this study, the sol–gel method was applied to the synthesis of CeO2 [...] Read more.
Cerium oxide nanoparticles (CeO2-NPs) have great applications in different industries, including nanomedicine. However, some studies report CeO2-NPs-related toxicity issues that limit their usage and efficiency. In this study, the sol–gel method was applied to the synthesis of CeO2-NPs using poly(allylamine) (PAA) as a capping and/or stabilizing agent. The different molecular weights of PAA (15,000, 17,000, and 65,000 g/mol) were used to investigate the physico-chemical and biological properties of the NPs. In order to understand their performance as an anticancer agent, three cell lines (MCF7, HeLa, and erythrocyte) were analyzed by MTT assay and RBC hemolysis assay. The results showed that the CeO2-NPs had anticancer effects on the viability of MCF7 cells with half-maximal inhibitory concentration (IC50) values of 17.44 ± 7.32, 6.17 ± 1.68, and 0.12 ± 0.03 μg/mL for PAA15000, PAA17000, PAA65000, respectively. As for HeLa cells, IC50 values reduced considerably to 8.09 ± 1.55, 2.11 ± 0.33, and 0.20 ± 0.01 μg/mL, in order. A decrease in the viability of cancer cells was associated with the 50% hemolytic concentration (HC50) of 0.022 ± 0.001 mg/mL for PAA15000, 3.74 ± 0.58 mg/mL for PAA17000, and 7.35 ± 1.32 mg/mL for PAA65000. Ultraviolet-Visible (UV-vis) spectroscopy indicated that an increase in the PAA molecular weight led to a blue shift in the bandgap and high amounts of Ce3+ on the surface of the nanoceria. Thus, PAA65000 could be considered as a biocompatible nanoengineered biomaterial for potential applications in cancer nanomedicine. Full article
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14 pages, 4376 KiB  
Article
Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption
by Guillermo Vilariño-Feltrer, Alfredo Salgado-Gallegos, Joan de-la-Concepción-Ausina, José Carlos Rodríguez-Hernández, Mohsen Shahrousvand and Ana Vallés-Lluch
Polymers 2020, 12(6), 1256; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12061256 - 30 May 2020
Cited by 5 | Viewed by 2272
Abstract
A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form [...] Read more.
A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction). Full article
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15 pages, 3718 KiB  
Article
Oxygen-Releasing Antibacterial Nanofibrous Scaffolds for Tissue Engineering Applications
by Turdimuhammad Abdullah, Kalamegam Gauthaman, Ahmed H. Hammad, Kasturi Joshi Navare, Ahmed A. Alshahrie, Sidi A. Bencherif, Ali Tamayol and Adnan Memic
Polymers 2020, 12(6), 1233; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12061233 - 29 May 2020
Cited by 42 | Viewed by 4959
Abstract
Lack of suitable auto/allografts has been delaying surgical interventions for the treatment of numerous disorders and has also caused a serious threat to public health. Tissue engineering could be one of the best alternatives to solve this issue. However, deficiency of oxygen supply [...] Read more.
Lack of suitable auto/allografts has been delaying surgical interventions for the treatment of numerous disorders and has also caused a serious threat to public health. Tissue engineering could be one of the best alternatives to solve this issue. However, deficiency of oxygen supply in the wounded and implanted engineered tissues, caused by circulatory problems and insufficient angiogenesis, has been a rate-limiting step in translation of tissue-engineered grafts. To address this issue, we designed oxygen-releasing electrospun composite scaffolds, based on a previously developed hybrid polymeric matrix composed of poly(glycerol sebacate) (PGS) and poly(ε-caprolactone) (PCL). By performing ball-milling, we were able to embed a large percent of calcium peroxide (CP) nanoparticles into the PGS/PCL nanofibers able to generate oxygen. The composite scaffold exhibited a smooth fiber structure, while providing sustainable oxygen release for several days to a week, and significantly improved cell metabolic activity due to alleviation of hypoxic environment around primary bone-marrow-derived mesenchymal stem cells (BM-MSCs). Moreover, the composite scaffolds also showed good antibacterial performance. In conjunction to other improved features, such as degradation behavior, the developed scaffolds are promising biomaterials for various tissue-engineering and wound-healing applications. Full article
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15 pages, 2873 KiB  
Review
Agarose-Based Biomaterials: Opportunities and Challenges in Cartilage Tissue Engineering
by Mohammad Amin Salati, Javad Khazai, Amir Mohammad Tahmuri, Ali Samadi, Ali Taghizadeh, Mohsen Taghizadeh, Payam Zarrintaj, Josh D. Ramsey, Sajjad Habibzadeh, Farzad Seidi, Mohammad Reza Saeb and Masoud Mozafari
Polymers 2020, 12(5), 1150; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12051150 - 18 May 2020
Cited by 114 | Viewed by 8484
Abstract
The lack of adequate blood/lymphatic vessels as well as low-potential articular cartilage regeneration underlines the necessity to search for alternative biomaterials. Owing to their unique features, such as reversible thermogelling behavior and tissue-like mechanical behavior, agarose-based biomaterials have played a key role in [...] Read more.
The lack of adequate blood/lymphatic vessels as well as low-potential articular cartilage regeneration underlines the necessity to search for alternative biomaterials. Owing to their unique features, such as reversible thermogelling behavior and tissue-like mechanical behavior, agarose-based biomaterials have played a key role in cartilage tissue repair. Accordingly, the need for fabricating novel highly efficient injectable agarose-based biomaterials as hydrogels for restoration of injured cartilage tissue has been recognized. In this review, the resources and conspicuous properties of the agarose-based biomaterials were reviewed. First, different types of signals together with their functionalities in the maintenance of cartilage homeostasis were explained. Then, various cellular signaling pathways and their significant role in cartilage tissue engineering were overviewed. Next, the molecular structure and its gelling behavior have been discussed. Eventually, the latest advancements, the lingering challenges, and future ahead of agarose derivatives from the cartilage regeneration perspective have been discussed. Full article
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15 pages, 3258 KiB  
Article
Morphology Dependence Degradation of Electro- and Magnetoactive Poly(3-hydroxybutyrate-co-hydroxyvalerate) for Tissue Engineering Applications
by Luis Amaro, Daniela M. Correia, Pedro M. Martins, Gabriela Botelho, Sónia A. C. Carabineiro, Clarisse Ribeiro and Senentxu Lanceros-Mendez
Polymers 2020, 12(4), 953; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12040953 - 20 Apr 2020
Cited by 19 | Viewed by 3440
Abstract
Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a piezoelectric biodegradable and biocompatible polymer suitable for tissue engineering applications. The incorporation of magnetostrictive cobalt ferrites (CFO) into PHBV matrix enables the production of magnetically responsive composites, which proved to be effective in the differentiation of a variety of [...] Read more.
Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a piezoelectric biodegradable and biocompatible polymer suitable for tissue engineering applications. The incorporation of magnetostrictive cobalt ferrites (CFO) into PHBV matrix enables the production of magnetically responsive composites, which proved to be effective in the differentiation of a variety of cells and tissues. In this work, PHBV and PHBV with CFO nanoparticles were produced in the form of films, fibers and porous scaffolds and subjected to an experimental program allowing to evaluate the degradation process under biological conditions for a period up to 8 weeks. The morphology, physical, chemical and thermal properties were evaluated, together with the weight loss of the samples during the in vitro degradation assays. No major changes in the mentioned properties were found, thus proving its applicability for tissue engineering applications. Degradation was apparent from week 4 and onwards, leading to the conclusion that the degradation ratio of the material is suitable for a large range of tissue engineering applications. Further, it was found that the degradation of the samples maintain the biocompatibility of the materials for the pristine polymer, but can lead to cytotoxic effects when the magnetic CFO nanoparticles are exposed, being therefore needed, for magnetoactive applications, to substitute them by biocompatible ferrites, such as an iron oxide (Fe3O4). Full article
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22 pages, 2274 KiB  
Review
Recent Advances in Tissue Adhesives for Clinical Medicine
by Liangpeng Ge and Shixuan Chen
Polymers 2020, 12(4), 939; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12040939 - 18 Apr 2020
Cited by 86 | Viewed by 11205
Abstract
Tissue adhesives have attracted more attention to the applications of non-invasive wound closure. The purpose of this review article is to summarize the recent progress of developing tissue adhesives, which may inspire researchers to develop more outstanding tissue adhesives. It begins with a [...] Read more.
Tissue adhesives have attracted more attention to the applications of non-invasive wound closure. The purpose of this review article is to summarize the recent progress of developing tissue adhesives, which may inspire researchers to develop more outstanding tissue adhesives. It begins with a brief introduction to the emerging potential use of tissue adhesives in the clinic. Next, several critical mechanisms for adhesion are discussed, including van der Waals forces, capillary forces, hydrogen bonding, static electric forces, and chemical bonds. This article further details the measurement methods of adhesion and highlights the different types of adhesive, including natural or biological, synthetic and semisynthetic, and biomimetic adhesives. Finally, this review article concludes with remarks on the challenges and future directions for design, fabrication, and application of tissue adhesives in the clinic. This review article has promising potential to provide novel creative design principles for the generation of future tissue adhesives. Full article
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9 pages, 2515 KiB  
Article
Biological Effects of Polyrotaxane Surfaces on Cellular Responses of Fibroblast, Preosteoblast and Preadipocyte Cell Lines
by Hiroki Masuda, Yoshinori Arisaka, Ruriko Sekiya-Aoyama, Tetsuya Yoda and Nobuhiko Yui
Polymers 2020, 12(4), 924; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12040924 - 16 Apr 2020
Cited by 8 | Viewed by 2754
Abstract
Biointerfaces based on polyrotaxane (PRX), consisting of α-cyclodextrins (α-CDs) threaded on a poly(ethylene glycol) (PEG) chain, are promising functionalized platforms for culturing cells. PRXs are characterized by the molecular mobility of constituent molecules where the threading α-CDs can move and rotate along the [...] Read more.
Biointerfaces based on polyrotaxane (PRX), consisting of α-cyclodextrins (α-CDs) threaded on a poly(ethylene glycol) (PEG) chain, are promising functionalized platforms for culturing cells. PRXs are characterized by the molecular mobility of constituent molecules where the threading α-CDs can move and rotate along the PEG chain. Taking advantage of this mobility, we have previously succeeded in demonstrating the regulation of cellular responses, such as cellular adhesion, proliferation, and differentiation. In the present study, we investigated differences in the cellular responses to PRX surfaces versus commercially available tissue culture polystyrene (TCPS) surfaces using fibroblasts, preosteoblasts, and preadipocytes. PRX surfaces were found to more significantly promote cellular proliferation than the TCPS surfaces, regardless of the cell type. To identify the signaling pathways involved in the activation of cellular proliferation, a DNA microarray analysis was performed. PRX surfaces showed a significant increase in the integrin-mediated cell adhesion and focal adhesion pathways. Furthermore, PRX surfaces also promoted osteoblast differentiation more than TCPS. These results suggest that structural features of PRX surfaces act as mechanical cues to dominate cellular proliferation and differentiation. Full article
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13 pages, 2909 KiB  
Article
Characterization of Thermal Damage Due to Two-Temperature High-Order Thermal Lagging in a Three-Dimensional Biological Tissue Subjected to a Rectangular Laser Pulse
by Hamdy M. Youssef and Najat. A. Alghamdi
Polymers 2020, 12(4), 922; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12040922 - 16 Apr 2020
Cited by 10 | Viewed by 1996
Abstract
The use of lasers and thermal transfers on the skin is fundamental in medical and clinical treatments. In this paper, we constructed and applied bioheat transfer equations in the context of a two-temperature heat conduction model in order to discuss the three-dimensional variation [...] Read more.
The use of lasers and thermal transfers on the skin is fundamental in medical and clinical treatments. In this paper, we constructed and applied bioheat transfer equations in the context of a two-temperature heat conduction model in order to discuss the three-dimensional variation in the temperature of laser-irradiated biological tissue. The amount of thermal damage in the tissue was calculated using the Arrhenius integral. Mathematical difficulties were encountered in applying the equations. As a result, the Laplace and Fourier transform technique was employed, and solutions for the conductive temperature and dynamical temperature were obtained in the Fourier transform domain. Full article
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13 pages, 2543 KiB  
Article
The Role of Two-Step Blending in the Properties of Starch/Chitin/Polylactic Acid Biodegradable Composites for Biomedical Applications
by Niyi Gideon Olaiya, Arif Nuryawan, Peter Kayode Oke, H. P. S. Abdul Khalil, Samsul Rizal, P. B. Mogaji, E. R. Sadiku, S. R. Suprakas, Peter Kayode Farayibi, Vincent Ojijo and M. T. Paridah
Polymers 2020, 12(3), 592; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12030592 - 05 Mar 2020
Cited by 13 | Viewed by 3953
Abstract
The current research trend for excellent miscibility in polymer mixing is the use of plasticizers. The use of most plasticizers usually has some negative effects on the mechanical properties of the resulting composite and can sometimes make it toxic, which makes such polymers [...] Read more.
The current research trend for excellent miscibility in polymer mixing is the use of plasticizers. The use of most plasticizers usually has some negative effects on the mechanical properties of the resulting composite and can sometimes make it toxic, which makes such polymers unsuitable for biomedical applications. This research focuses on the improvement of the miscibility of polymer composites using two-step mixing with a rheomixer and a mix extruder. Polylactic acid (PLA), chitin, and starch were produced after two-step mixing, using a compression molding method with decreasing composition variation (between 8% to 2%) of chitin and increasing starch content. A dynamic mechanical analysis (DMA) was used to study the mechanical behavior of the composite at various temperatures. The tensile strength, yield, elastic modulus, impact, morphology, and compatibility properties were also studied. The DMA results showed a glass transition temperature range of 50 °C to 100 °C for all samples, with a distinct peak value for the loss modulus and factor. The single distinct peak value meant the polymer blend was compatible. The storage and loss modulus increased with an increase in blending, while the loss factor decreased, indicating excellent compatibility and miscibility of the composite components. The mechanical properties of the samples improved compared to neat PLA. Small voids and immiscibility were noticed in the scanning electron microscopy images, and this was corroborated by X-ray diffraction graphs that showed an improvement in the crystalline nature of PLA with starch. Bioabsorption and toxicity tests showed compatibility with the rat system, which is similar to the human system. Full article
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10 pages, 8343 KiB  
Article
Rapid Photoinduced Single Cell Detachment from Gold Nanoparticle-Embedded Collagen Gels with Low Denaturation Temperature
by Chie Kojima, Misaki Nishio, Yusuke Nakajima, Takeshi Kawano, Kenji Takatsuka and Akikazu Matsumoto
Polymers 2020, 12(1), 213; https://0-doi-org.brum.beds.ac.uk/10.3390/polym12010213 - 15 Jan 2020
Cited by 4 | Viewed by 3316
Abstract
Cell Separation is important in various biomedical fields. We have prepared gold nanoparticle (AuNP)-embedded collagen gels as a visible-light-responsive cell scaffold in which photoinduced single cell detachment occurs through local thermal denaturation of the collagen gel via the photothermal effect of AuNP. Physicochemical [...] Read more.
Cell Separation is important in various biomedical fields. We have prepared gold nanoparticle (AuNP)-embedded collagen gels as a visible-light-responsive cell scaffold in which photoinduced single cell detachment occurs through local thermal denaturation of the collagen gel via the photothermal effect of AuNP. Physicochemical properties of collagen materials depend on the origin of the collagen and the presence of telopeptides. In this study, we prepared various AuNP-embedded collagen gels by using different collagen materials with and without the telopeptides to compare their thermal denaturation properties and photoinduced single cell detachment behaviors. Cellmatrix type I-C without telopeptides exhibited a lower denaturation temperature than Cellmatrix type I-A and Atelocell IAC, as examined by Fourier transform infrared (FTIR) spectroscopy, rheological analysis, and sol–gel transition observation. Three-dimensional (3D) laser microscopic imaging revealed that collagen fibers shrank in Cellmatrix type I-A upon heating, but collagen fibers disappeared in Cellmatrix type I-C upon heating. Cells cultured on the Cellmatrix type I-C-based AuNP-embedded collagen gel detached with shorter photoirradiation than on the Cellmatrix type I-A-based AuNP-embedded collagen gel, suggesting that collagen gels without telopeptides are suitable for a photoinduced single cell detachment system. Full article
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2019

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13 pages, 4528 KiB  
Article
PH-Sensitive, Polymer Functionalized, Nonporous Silica Nanoparticles for Quercetin Controlled Release
by Lin Xu, Hong-Liang Li and Li-Ping Wang
Polymers 2019, 11(12), 2026; https://0-doi-org.brum.beds.ac.uk/10.3390/polym11122026 - 06 Dec 2019
Cited by 18 | Viewed by 3622
Abstract
Some pH-sensitive, poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) grafted silica nanoparticles (SNPs) (SNPs-g-PDEAEMA) were designed and synthesized via surface initiated, metal-free, photoinduced atom transfer radical polymerization (ATRP). The structures of the polymers formed in solution were determined by 1H NMR. The modified nanoparticles [...] Read more.
Some pH-sensitive, poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) grafted silica nanoparticles (SNPs) (SNPs-g-PDEAEMA) were designed and synthesized via surface initiated, metal-free, photoinduced atom transfer radical polymerization (ATRP). The structures of the polymers formed in solution were determined by 1H NMR. The modified nanoparticles were characterized by FT-IR spectroscopy, XPS, GPC, TEM and TGA. The analytical results show that α-bromoisobutyryl bromide (BIBB) (ATRP initiator) had been successfully anchored onto SNPs’ surfaces, and was followed by surface-initiated, metal-free ATRP of 2-(diethylamino)ethyl methacrylate (DEAEMA). The resultant SNPs-g-PDEAEMA were uniform spherical nanoparticles with the particles size of about 22–25 nm, and the graft density of PDEAEMA on SNPs’ surfaces obtained by TGA was 19.98 μmol/m2. Owing to the covalent grafting of pH-sensitive PDEAEMA, SNPs-g-PDEAEMA can dispersed well in acidic aqueous solution, but poorly in neutral and alkaline aqueous solutions, which is conducive to being employed as drug carriers to construct a pH-sensitive controlled drug delivery system. In vitro cytotoxicity evaluation results showed that the cytotoxicity of SNPs-g-PDEAEMA to the L929 cells had completely disappeared on the 3rd day. The loading of quercetin on SNPs-g-PDEAEMA was performed using adsorption process from ethanol solutions, and the dialysis release rate increased sharply when the pH value of phosphate-buffered saline (PBS) decreased from 7.4 to 5.5. All these results indicated that the pH-responsive microcapsules could serve as potential anti-cancer drug carriers. Full article
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21 pages, 419 KiB  
Review
Pharmacologic Application Potentials of Sulfated Polysaccharide from Marine Algae
by Joanne Katherine Talens Manlusoc, Chieh-Lun Hsieh, Cheng-Yang Hsieh, Ellen San Nicolas Salac, Ya-Ting Lee and Po-Wei Tsai
Polymers 2019, 11(7), 1163; https://0-doi-org.brum.beds.ac.uk/10.3390/polym11071163 - 08 Jul 2019
Cited by 59 | Viewed by 6407
Abstract
With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to [...] Read more.
With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to the isolation of active compounds with biological activities, such as antioxidation of free radicals, anti-inflammation, antiproliferation of cancer cells, and anticoagulant to name a few. One of the compounds that are isolated from marine algae are sulfated polysaccharides (SPs). SPs are complex heterogenous natural polymers with an abundance found in different species of marine algae. Marine algae are known to be one of the most important sources of SPs, and depending on the species, its chemical structure varies. This variety has important physical and chemical components and functions which has gained the attention of researchers as this contributes to the many facets of its pharmacologic activity. In this review, recent pharmacologic application potentials and updates on the use of SPs from marine algae are discussed. Full article
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10 pages, 1683 KiB  
Article
Design of Controlled Release System for Paracetamol Based on Modified Lignin
by Mahboubeh Pishnamazi, Hamid Hafizi, Saeed Shirazian, Mario Culebras, Gavin M. Walker and Maurice N. Collins
Polymers 2019, 11(6), 1059; https://0-doi-org.brum.beds.ac.uk/10.3390/polym11061059 - 18 Jun 2019
Cited by 75 | Viewed by 7129
Abstract
The influence of lignin modification on drug release and pH-dependent releasing behavior of oral solid dosage forms was investigated using three different formulations. The first formulation contains microcrystalline cellulose (MCC 101) as the excipient and paracetamol as the active pharmaceutical ingredient (API). The [...] Read more.
The influence of lignin modification on drug release and pH-dependent releasing behavior of oral solid dosage forms was investigated using three different formulations. The first formulation contains microcrystalline cellulose (MCC 101) as the excipient and paracetamol as the active pharmaceutical ingredient (API). The second formulation includes Alcell lignin and MCC 101 as the excipient and paracetamol, and the third formulation consists of carboxylated Alcell lignin, MCC 101 and paracetamol. Direct compaction was carried out in order to prepare the tablets. Lignin can be readily chemically modified due to the existence of different functional groups in its structure. The focus of this investigation is on lignin carboxylation and its influence on paracetamol control release behavior at varying pH. Results suggest that carboxylated lignin tablets had the highest drug release, which is linked to their faster disintegration and lower tablet hardness. Full article
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