In this study, dissolving polymeric microneedle (MN) patches composed of gelatin and sodium carboxymethyl cellulose (CMC) were used to localize insulin. Their in vitro skin insertion capabilities were determined using tissue-marking dye to stain the skin after patches removal. Scanning electron microscopy (SEM) was used to determine changes in the MNs over time, and optical coherence tomography (OCT) was used to monitor their real-time penetration depth. Confocal microscopy images revealed that rhodamine 6G gradually diffuses from the puncture sites to deeper dermal tissue. Using an in vivo imaging system (IVIS), skin areas that received FITC-insulin-loaded MNs were found to present strong fluorescent signals that greatly decreased 1 h after application. Results show that dissolving MNs rapidly release FITC-insulin, and it then gradually diffuses into the skin. This study verifies that using a gelatin/CMC MN patch for insulin delivery achieves satisfactory relative bioavailability compared to a traditional hypodermic injection and can be a promising delivery device for poorly permeable protein drugs such as those used to treat diabetes. Insertion tests on human cadaveric skin demonstrate that dissolving MNs could serve as efficient devices for transdermal drug delivery in clinical practice and that the volar aspect of forearm skin is the ideal location for their applications. Full article

Polymeric scaffolds such as hydrogels can be engineered to restore, maintain, or improve impaired tissues and organs. However, most hydrogels require surgical implantation that can cause several complications such as infection and damage to adjacent tissues. Therefore, developing minimally invasive strategies is of critical importance for these purposes. Herein, we developed several injectable cryogels made out of hyaluronic acid and gelatin for tissue-engineering applications. The physicochemical properties of hyaluronic acid combined with the intrinsic cell-adhesion properties of gelatin can provide suitable physical support for the attachment, survival, and spreading of cells. The physical characteristics of pure gelatin cryogels, such as mechanics and injectability, were enhanced once copolymerized with hyaluronic acid. Reciprocally, the adhesion of 3T3 cells cultured in hyaluronic acid cryogels was enhanced when formulated with gelatin. Furthermore, cryogels had a minimal effect on bone marrow dendritic cell activation, suggesting their cytocompatibility. Finally, in vitro studies revealed that copolymerizing gelatin with hyaluronic acid did not significantly alter their respective intrinsic biological properties. These findings suggest that hyaluronic acid-co-gelatin cryogels combined the favorable inherent properties of each biopolymer, providing a mechanically robust, cell-responsive, macroporous, and injectable platform for tissue-engineering applications. Full article

The agglomeration of silver nanoparticles (AgNPs) results in poor antibacterial performance, and the accumulation of silver in the human body threatens human health. Preparing a matrix is a technique worth considering as it not only prevents the aggregation of AgNPs but also reduces deposition of AgNPs in the human body. In this paper, carboxy-cellulose nanocrystals (CCNC) were prepared by a simple one-step acid hydrolysis method. Chito-oligosaccharides (CSos) were grafted onto the surface of CCNC to form CSos-CCNC composite nanoparticles. CCNC and CSos-CCNC were used as stabilizers for deposing AgNPs and two types of complexes—AgNPs-CCNC and AgNPs-CSos-CCNC—were obtained, respectively. The influence of the two stabilizer matrices—CCNC and CSos-CCNC—on the morphology, thermal behavior, crystal structure, antibacterial activity, and cell compatibility of AgNPs-CCNC and AgNPs-CSos-CCNC were examined. The results showed that the AgNPs deposited on the CSos-CCNC surface had a smaller average diameter and a narrower particle size distribution compared with the ones deposited on CCNC. The thermal stability of AgNPs-CSos-CCNC was better than that of AgNPs-CCNC. AgNPs did not affect the crystalline structure of CCNC and CSos-CCNC. The antibacterial activity of AgNPs-CSos-CCNC was better than that of AgNPs-CCNC based on antibacterial studies using Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae. The cytotoxicity of AgNPs-CSos-CCNC was remarkably lower than that of AgNPs-CCNC. Full article

Cytokines and chemokines play important roles in cell signalling, and microdialysis is a promising tool for monitoring these inflammation markers ex vivo. Therefore, the collecting of these mediators at the highest concentrations possible is crucial. Depending on the size of the mediator of interest, the collection of these high molecular mass molecules has thus far been difficult due to their low recovery, even when using high cut-off (100 kDa) microdialysis membranes. This study aimed to optimize the recovery of various cytokines and chemokines by validating the use of different perfusates in cutaneous microdialysis, and comparing intravenous (i.v.) colloids, crystalloids, and a lipid emulsion formulations that are approved for i.v. applications. Methods: In vitro and in vivo recovery experiments using six recombinant cytokines varying in molecular size (interleukin-2 (15 kDa), interleukin-6 (20.5 kDa), interleukin-8 (8 kDa), interleukin-12p70 (70 kDa), TNF-α (17.5 kDa), and vascular endothelial growth factor (VEGF) (38 kDa)) were performed in the presence of different perfusates for i.v. applications: Ringer’s lactate, dextran 60 kDa, hydroxyethyl starch 70 kDa, and hydroxyethyl starch 200 kDa solutions as well as a lipid emulsion formulation. Recovery was determined through (i) microdialysis of cytokines and chemokines in Ringer’s lactate solution or human serum in vitro, and (ii) retrodialysis of excised porcine and human skin cadavers in vitro and porcine skin in vivo. Furthermore, we used skin trauma (catheter insertion) and Ultraviolet B irradiation of 3 × 3 cm² skin areas to sample cytokines and chemokines in vivo and compared the amounts that were obtained using crystalloid and colloid perfusates. All the cytokines and chemokines within the dialysates were quantified through a flow cytometry-based bead array assay. Results: Overall, recovery was strongly increased by the colloids, particularly hydroxyethyl starch 70 kDa, in vitro, ex vivo, and in vivo. When compared with the recovery achieved using Ringer’s lactate, this increase was most effective for proteins ranging from 8 to 20.5 kDa. Hydroxyethyl starch 70 kDa significantly increased the recovery of interleukin (IL)-8 in human serum in vitro when compared with Ringer’s lactate. More cytokines and chemokines were recovered using colloids compared with crystalloids. However, the increase in recovery values was lower for IL-12p70 and VEGF. Conclusions: Regarding the dialysate volumes and final dialysate concentrations, colloid perfusates are overall superior to crystalloid perfusates, such as Ringer’s lactate, when sampling cytokines and chemokines, resulting in higher recoveries. However, the sampling of high-molecular-mass cytokines during microdialysis remains challenging, and experimental in vitro data are not completely comparable with data obtained ex vivo or in vivo. Full article

Chitin and lignin primarily accumulate as bio-waste resulting from byproducts of crustacean crusts and plant biomass. Recently, their use has been proposed for diverse and unique bioengineering applications, amongst others. However, their weak mechanical properties need to be improved in order to facilitate their industrial utilization. In this paper, we fabricated hybrid fibers composed of a chitin–lignin (CL)-based sol–gel mixture and elastomeric poly (glycerol sebacate) (PGS) using a standard electrospinning approach. Obtained results showed that PGS could be coherently blended with the sol–gel mixture to form a nanofibrous scaffold exhibiting remarkable mechanical performance and improved antibacterial and antifungal activity. The developed hybrid fibers showed promising potential in advanced biomedical applications such as wound care products. Ultimately, recycling these sustainable biopolymers and other bio-wastes alike could propel a “greener” economy. Full article

During hemodialysis (HD), blood is circulated through an extracorporeal tubing system (bloodline) made of medical-grade polymeric material. Sensors of various types that do not come into contact with blood (optical, electromagnetic, etc.) are applied directly across the bloodline for clinical purposes and for therapy customization. Thus, a detailed knowledge of the bloodline’s physical properties is useful for the development of next-generation HD sensors. In this work, we performed a novel comparative analysis of the materials used by the manufacturers of the bloodlines. We focused on signals and characterization techniques matching those of the abovementioned sensors; consequently, this is an application-specific study of the optical and electrical characterization of bloodline material. Such properties are analyzed and compared for bloodlines from seven different manufacturers by optical absorbance spectroscopy and electrical impedance spectroscopy (EIS). Absorbance spectrum measurements are carried out in the VIS-NIR range. Absorbance spectra are pre-processed and data from both types of analyses are normalized with respect to sample thickness. Optical analysis shows that all bloodlines except one have similarly shaped spectra with slight quantitative differences. In all optical spectra, we find a decreasing trend of specific absorption from 0.14 mm⁻¹ at 400 nm to 0.06 mm⁻¹ at 1000 nm, with an absorption peak at 915 nm. In one case, a large absorption peak centered at ≃600 nm is found. Electrical analysis shows that all bloodlines have the electrical properties of a constant-phase element (CPE), with statistically significant differences in parameters’ values. Estimation of electrical CPE parameters for all bloodline returns a range of 0.942–0.957 for parameter n and a range of 12.41–16.64 for parameter Q₀’. In conclusion, we find that, although some statistically significant differences are present, bloodlines from a representative group of manufacturers share similar electrical and optical properties. Therefore, contactless sensing devices developed for HD will work on different bloodlines if a simple recalibration is performed. Full article

Colonization of silicone-based soft lining materials by pathogenic yeast-type fungi is a common problem associated with the use of dentures. In this study, silver sodium hydrogen zirconium phosphate (SSHZP) was introduced into polydimethylsiloxane-based material as an antimicrobial filler at concentrations of 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, and 14% (w/w). The in vitro antimicrobial efficacy was investigated. Candida albicans was used as a characteristic representative of pathogenic oral microflora. Staphylococcus aureus and Escherichia coli were used as the typical Gram-positive and Gram-negative bacterial strains, respectively. The effect of filler addition on the Shore A hardness, tensile strength, tensile bond strength, sorption, and solubility was investigated. An increase in the filler concentration resulted in an increase in hardness, sorption, and solubility, and for the highest concentration, a decrease in bond strength. The favorable combination of antimicrobial efficacy with other properties was achieved at filler concentrations ranging from 2% to 10%. These composites exhibited mechanical properties similar to the material without the antimicrobial filler and enhanced in vitro antimicrobial efficiency. Full article

Poly-N-isopropylacrylamide (polyNIPA) is an extensively studied polymer in the field of controlled drug delivery. PolyNIPA contains carbonyl and amide groups along a hydrophobic chain. In an aqueous environment, crosslinked polyNIPA forms a gel characterized by a reversible volume phase transition temperature (VPTT), in response to changes in the external environment excited by the temperature factor. NIPA-based polymers were synthesized by a surfactant-free precipitation polymerization (SFPP) method at a temperature of 70 °C using the free radical initiator potassium persulfate (KPS) and at 35 °C using redox initiator system KPS with N,N,N’,N’-tetramethylethylenediamine (TEMED). The synthesized products were evaluated via dynamic light scattering (DLS), nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). The chemical structure, molecular mass, and hydrodynamic diameter of obtained particles, as well as the effects of synthesized polymers on the release of the active substance, naproxen sodium (NS), from hydroxypropyl methyl cellulose (HPMC)-based hydrogels were assessed. The use of the TEMED activator affected the particle size, as well as the release kinetics of NS. The insertion of TEMED into reactant mixtures may be applied to modify the release kinetics of NS from hydrogel preparations. Full article

Insufficient bone volume is one of the major challenges encountered by dentists after dental implant placement. This study aimed to evaluate the efficacy of a customized three-dimensional polycaprolactone (3D PCL) scaffold implant fabricated with a 3D bio-printing system to facilitate rapid alveolar bone regeneration. Saddle-type bone defects were surgically created on the healed site after extracting premolars from the mandibles of four beagle dogs. The defects were radiologically examined using computed tomography for designing a customized 3D PCL scaffold block to fit the defect site. After fabricating 3D PCL scaffolds using rapid prototyping, the scaffolds were implanted into the alveolar bone defects along with β-tricalcium phosphate powder. In vivo analysis showed that the PCL blocks maintained the physical space and bone conductivity around the defects. In addition, no inflammatory infiltrates were observed around the scaffolds. However, new bone formation occurred adjacent to the scaffolds, rather than directly in contact with them. More new bone was observed around PCL blocks with 400/1200 lattices than around blocks with 400/400 lattices, but the difference was not significant. These results indicated the potential of 3D-printed porous PCL scaffolds to promote alveolar bone regeneration for defect healing in dentistry. Full article

Dental bulk-fill restorations with resin-composites (RBC) are increasing in popularity, but doubts concerning insufficient curing in depth still disconcert clinicians. An alternative might be offered by modern dual-cured RBCs, which additionally provide bioactive properties. This study assessed the impact of additional light-curing on polymerization kinetics, the degree of conversion (DC) and mechanical properties of a novel, dual-cured RBC with alkaline fillers. Since the bioactivity of a material often implies a release of compounds, the mechanical stability in simulated clinical environments was also evaluated. Polymerization kinetics and DC were assessed at 2- and 4-mm specimen depths in real-time up to one hour (n = 6). Incident and transmitted irradiance and radiant exposure were recorded at 2- and 4-mm depths. Micro-mechanical profiles (n = 6) were assessed in 100-µm steps along 6-mm deep specimens at 24 h post-polymerization. Flexural strength and modulus (n = 10) were determined up to three months of immersion in neutral (6.8) and acidic (4) pH conditions. DC variation in time was best described by a sigmoidal function (R² > 0.98), revealing a retarded (3.4 ± 0.4 min) initiation in C=C double bond conversion in self-cured versus dual-cured specimens. The setting reaction kinetic was identical at 2- and 4-mm depths for the self-cure mode. For the dual-cure mode, polymerization initiated at 2-mm depth instantly with light-irradiation, while being retarded (0.8 min) at 4-mm depth. The material behaves similarly, irrespective of curing mode or depth, later than 11 min after mixing. Flexural strength and modulus was comparable to regular RBCs and maintained up to three months in both neutral and acidic conditions. Additional light-curing initially accelerates the polymerization kinetic and might help shorten the restauration procedure by hardening the material on demand, however with no effect on the final properties. Full article

Nanoparticles or microparticles created by physical complexation between two polyelectrolytes may have a prospective use as an excipient for oral insulin administration. Natural polymers such as tragacanth, alginate, dextran, pullulan, hyaluronic acid, gelatin and chitosan can be potential candidates for this purpose. In this research, insulin particles were prepared by the inclusion of insulin into a tragacanth hydrogel. The effect of the pH and concentration relationship involving polyelectrolytes offering individual particle size and zeta potential was assessed by zetasizer and scanning electron microscopy (SEM). Insulin–tragacanth interactions at varying pH (3.7, 4.3, 4.6, or 6), and concentration (0.1%, 0.5%, or 1% w/w) were evaluated by differential scanning calorimetry (DSC) and ATR Fourier transform infrared (ATR-FTIR) analysis. Individual and smaller particles, approximately 800 nm, were acquired at pH 4.6 with 0.5% of tragacanth. The acid gelation test indicated that insulin could be entrapped in the physical hydrogel of tragacanth. DSC thermograms of insulin–tragacanth showed shifts on the same unloaded tragacanth peaks and suggested polyelectrolyte–protein interactions at a pH close to 4.3–4.6. FTIR spectra of tragacanth–insulin complexes exhibited amide absorption bands featuring in the protein spectra and revealed the creation of a new chemical substance. Full article

The differentiation potential of mesenchymal stem cells (MSC) has been extensively tested on electrospun scaffolds. However, this potential is often assessed with lineage-specific medium, making it difficult to interpret the real contribution of the properties of the scaffold in the cell response. In this study, we analyzed the ability of different polycaprolactone/polylactic acid PCL/PLA electrospun scaffolds (pure or blended compositions, random or aligned fibers, various fiber diameters) to drive MSC towards bone or tendon lineages in the absence of specific differentiation medium. C3H10T1/2 cells (a mesenchymal stem cell model) were cultured on scaffolds for 96 h without differentiation factors. We performed a cross-analysis of the cell–scaffold interactions (spreading, organization, and specific gene expression) with mechanical (elasticity), morphological (porosity, fibers diameter and orientation) and surface (wettability) characterizations of the electrospun fibers. We concluded that (1) osteogenic differentiation can be initiated on pure PCL-based electrospun scaffolds without specific culture conditions; (2) fiber alignment modified cell organization in the short term and (3) PLA added to PCL with an increased fiber diameter encouraged the stem cells towards the tendon lineage without additional tenogenic factors. In summary, the differentiation potential of stem cells on adapted electrospun fibers could be achieved in factor-free medium, making possible future applications in clinically relevant situations. Full article

Titanium is widely used as a bone implant material due to its biocompatibility and high resilience. Since its Young’s modulus differs from bone tissue, the resulting “stress shielding” could lead to scaffold loosening. However, by using a scaffold-shaped geometry, the Young’s modulus can be adjusted. Also, a porous geometry enables vascularisation and bone ingrowth inside the implant itself. Additionally, growth factors can improve these effects. In order to create a deposit and release system for these factors, the titanium scaffolds could be coated with degradable polymers. Therefore, in the present study, synthetic poly-ε-caprolactone (PCL) and the biopolymer poly(3-hydroxybutyrate) (P(3HB)) were tested for coating efficiency, cell adhesion, and biocompatibility to find a suitable coating material. The underlying scaffold was created from titanium by Selective Laser Melting (SLM) and coated with PCL or P(3HB) via dip coating. To test the biocompatibility, Live Cell Imaging (LCI) as well as vitality and proliferation assays were performed. In addition, cell adhesion forces were detected via Single Cell Force Spectroscopy, while the coating efficiency was observed using environmental scanning electron microscopy (ESEM) and energy-dispersive X-ray (EDX) analyses. Regarding the coating efficiency, PCL showed higher values in comparison to P(3HB). Vitality assays revealed decent vitality values for both polymers, while values for PCL were significantly lower than those for blank titanium. No significant differences could be observed between PCL and P(3HB) in proliferation and cell adhesion studies. Although LCI observations revealed decreasing values in cell number and populated area over time on both polymer-coated scaffolds, these outcomes could be explained by the possibility of coating diluent residues accumulating in the culture medium. Overall, both polymers fulfill the requirements regarding biocompatibility. Nonetheless, since only PCL coating ensured the maintenance of the porous implant structure, it is preferable to be used as a coating material for creating a deposit and release system for growth factors. Full article

We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species. Cell uptake and cytotoxicity were evaluated by confocal microscopy, transmission electron microscopy, iron content and metabolic assays, utilizing multimodal tracking of membrane fluorophores and nanoparticles. Cationic functionalization of vesicles promoted endocytotic uptake. In particular, incorporation of cationic lipids in the polymersome membrane yielded tremendously increased uptake of polymersomes and magnetopolymersomes without increase in cytotoxicity. Ultrastructure investigations showed that cationic magnetopolymersomes disintegrated upon hydrolysis, including the dissolution of incorporated iron oxide nanoparticles. The presented platform could find future use in theranostic multimodal imaging in vivo and magnetically triggered delivery by incorporation of thermorepsonsive amphiphiles that can break the membrane integrity upon magnetic heating via the embedded superparamagnetic nanoparticles. Full article

Ceramic and metallic nanoparticles can improve the mechanical and biological properties of polymeric scaffolds for bone tissue engineering (BTE). In this work, nanohydroxyapatite (nHAp) and nano-copper-zinc alloy (nCuZn) were added to a chitosan/gelatin (Ch/G) scaffold in order to investigate the effects on morphological, physical, and biocompatibility properties. Scaffolds were fabricated by a freeze-drying technique using different pre-freezing temperatures. Microstructure and morphology were studied by scanning electron microscopy (SEM), glass transition (T_g) was studied using differential scanning calorimetry (DSC), cell growth was estimated by MTT assay, and biocompatibility was examined in vitro and in vivo by histochemistry analyses. Scaffolds and nanocomposite scaffolds presented interconnected pores, high porosity, and pore size appropriate for BTE. T_g of Ch/G scaffolds was diminished by nanoparticle inclusion. Mouse embryonic fibroblasts (MEFs) cells loaded in the Ch/G/nHAp/nCuZn nanocomposite scaffold showed suitable behavior, based on cell adhesion, cell growth, alkaline phosphatase (ALP) activity as a marker of osteogenic differentiation, and histological in vitro cross sections. In vivo subcutaneous implant showed granulation tissue formation and new tissue infiltration into the scaffold. The favorable microstructure, coupled with the ability to integrate nanoparticles into the scaffold by freeze-drying technique and the biocompatibility, indicates the potential of this new material for applications in BTE. Full article

Degradable bone graft substitute for large-volume bone defects is a continuously developing field in orthopedics. With the advance in biomaterial in past decades, a wide range of new materials has been investigated for their potential in this application. When compared to common biopolymers within the field such as PLA or PCL, elastomers such as polyurethane offer some unique advantages in terms of flexibility. In cases of bone defect treatments, a flexible soft filler can help to establish an intimate contact with surrounding bones to provide a stable bone-material interface for cell proliferation and ingrowth of tissue. In this study, a porous filler based on segmented polyurethane incorporated with poly l-lactic acid was synthesized by a phase inverse salt leaching method. The filler was put through in vitro and in vivo tests to evaluate its potential in acting as a bone graft substitute for critical-sized bone defects. In vitro results indicated there was a major improvement in biological response, including cell attachment, proliferation and alkaline phosphatase expression for osteoblast-like cells when seeded on the composite material compared to unmodified polyurethane. In vivo evaluation on a critical-sized defect model of New Zealand White (NZW) rabbit indicated there was bone ingrowth along the defect area with the introduction of the new filler. A tight interface formed between bone and filler, with osteogenic cells proliferating on the surface. The result suggested polyurethane/poly l-lactic acid composite is a material with the potential to act as a bone graft substitute for orthopedics application. Full article

In the present study, we propose and develop a flexible pressure sensor based on the piezoresistive effect of multilayer graphene films on polyester textile. The pressure response results from the deformation of graphene conductive network structure and the changes in resistance. Here, we show that the graphene pressure sensor can achieve a sensitivity value of 0.012 kPa ${}^{-1}$ , the measurement range can be as high as 800 kPa, and the response time can reach to 50 ms. Subsequently, a stable in-shoe wireless plantar pressure measurement system is developed and dynamic pressure distribution is acquired in real-time. Overall, the graphene textile pressure sensor has the advantage of wide dynamic range, flexibility and comfort, which provides the high possibility for footwear evaluation, clinical gait analysis and pathological foot diagnosis. Full article

Composite nanofibers of biopolymers and inorganic materials have been widely explored as tissue engineering scaffolds because of their superior structural, mechanical and biological properties. In this study, magnesium ferrite (Mg-ferrite) based composite nanofibers were synthesized using an electrospinning technique. Mg-ferrite nanoparticles were first synthesized using the reverse micelle method, and then blended in a mixture of polycaprolactone (PCL), a synthetic polymer, and Aloe vera, a natural polymer, to create magnetic nanofibers by electrospinning. The morphology, structural and magnetic properties, and cellular compatibility of the magnetic nanofibers were analyzed. Mg-ferrite/PCL/Aloe vera nanofibers showed good uniformity in fiber morphology, retained their structural integrity, and displayed magnetic strength. Experimental results, using cell viability assay and scanning electron microscopy imaging showed that magnetic nanofibers supported 3T3 cell viability. We believe that the new composite nanofibrous membranes developed in this study have the ability to mimic the physical structure and function of tissue extracellular matrix, as well as provide the magnetic and soluble metal ion attributes in the scaffolds with enhanced cell attachment, and thus improve tissue regeneration. Full article

Tremendous progress in stem cell biology has resulted in a major current focus on effective modalities to promote directed cellular behavior for clinical therapy. The fundamental principles of tissue engineering are aimed at providing soluble and insoluble biological cues to promote these directed biological responses. Better understanding of extracellular matrix functions is ensuring optimal adhesive substrates to promote cell mobility and a suitable physical niche to direct stem cell responses. Further, appreciation of the roles of matrix constituents as morphogen cues, termed matrikines or matricryptins, are also now being directly exploited in biomaterial design. These insoluble topological cues can be presented at both micro- and nanoscales with specific fabrication techniques. Progress in development and molecular biology has described key roles for a range of biological molecules, such as proteins, lipids, and nucleic acids, to serve as morphogens promoting directed behavior in stem cells. Controlled-release systems involving encapsulation of bioactive agents within polymeric carriers are enabling utilization of soluble cues. Using our efforts at dental craniofacial tissue engineering, this narrative review focuses on outlining specific biomaterial fabrication techniques, such as electrospinning, gas foaming, and 3D printing used in combination with polymeric nano- or microspheres. These avenues are providing unprecedented therapeutic opportunities for precision bioengineering for regenerative applications. Full article

The eye has many barriers with specific anatomies that make it difficult to deliver drugs to targeted ocular tissues, and topical administration using eye drops or ointments usually needs multiple instillations to maintain the drugs’ therapeutic concentration because of their low bioavailability. A drug-eluting contact lens is one of the more promising platforms for controllable ocular drug delivery, and, among various manufacturing methods for drug-eluting contact lenses, incorporation of novel polymeric vehicles with versatile features makes it possible to deliver the drugs in a sustained and extended manner. Using the diverse physicochemical properties of polymers for nanoparticles or implants that are selected according to the characteristics of drugs, enhancement of encapsulation efficiency and prolonged drug release are possible. Even though therapeutic contact lenses with polymeric vehicles allow us to achieve sustained ocular drug delivery, drug leaching during storage and distribution and the possibility of problems related to surface roughness due to the incorporated vehicles still need to be discussed before application in a real clinic. This review highlights the overall trends in methodology to develop therapeutic contact lenses with polymeric vehicles and discusses the limitations including comparison to cosmetically tinted soft contact lenses. Full article

Tissue engineering is a promising approach to repair tendon and muscle when natural healing fails. Biohybrid constructs obtained after cells’ seeding and culture in dedicated scaffolds have indeed been considered as relevant tools for mimicking native tissue, leading to a better integration in vivo. They can also be employed to perform advanced in vitro studies to model the cell differentiation or regeneration processes. In this review, we report and analyze the different solutions proposed in literature, for the reconstruction of tendon, muscle, and the myotendinous junction. They classically rely on the three pillars of tissue engineering, i.e., cells, biomaterials and environment (both chemical and physical stimuli). We have chosen to present biomimetic or bioinspired strategies based on understanding of the native tissue structure/functions/properties of the tissue of interest. For each tissue, we sorted the relevant publications according to an increasing degree of complexity in the materials’ shape or manufacture. We present their biological and mechanical performances, observed in vitro and in vivo when available. Although there is no consensus for a gold standard technique to reconstruct these musculo-skeletal tissues, the reader can find different ways to progress in the field and to understand the recent history in the choice of materials, from collagen to polymer-based matrices. Full article

Polymeric micelles are potentially efficient in encapsulating and performing the controlled release of various hydrophobic drug molecules. Understanding the fundamental physicochemical properties behind drug–polymer systems in terms of interaction strength and compatibility, drug partition coefficient (preferential solubilization), micelle size, morphology, etc., encourages the formulation of polymeric nanocarriers with enhanced drug encapsulating capacity, prolonged circulation time, and stability in the human body. In this review, we systematically address some open issues which are considered to be obstacles inhibiting the commercial availability of polymer-based therapeutics, such as the enhancement of encapsulation capacity by finding better drug–polymer compatibility, the drug-release kinetics and mechanisms under chemical and mechanical conditions simulating to physiological conditions, and the role of preparation methods and solvents on the overall performance of micelles. Full article

While polymers are widely utilized materials in the biomedical industry, they are rarely used in an unmodified state. Some kind of a surface treatment is often necessary to achieve properties suitable for specific applications. There are multiple methods of surface treatment, each with their own pros and cons, such as plasma and laser treatment, UV lamp modification, etching, grafting, metallization, ion sputtering and others. An appropriate treatment can change the physico-chemical properties of the surface of a polymer in a way that makes it attractive for a variety of biological compounds, or, on the contrary, makes the polymer exhibit antibacterial or cytotoxic properties, thus making the polymer usable in a variety of biomedical applications. This review examines four popular methods of polymer surface modification: laser treatment, ion implantation, plasma treatment and nanoparticle grafting. Surface treatment-induced changes of the physico-chemical properties, morphology, chemical composition and biocompatibility of a variety of polymer substrates are studied. Relevant biological methods are used to determine the influence of various surface treatments and grafting processes on the biocompatibility of the new surfaces—mammalian cell adhesion and proliferation is studied as well as other potential applications of the surface-treated polymer substrates in the biomedical industry. Full article