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20 pages, 5550 KiB

Open AccessArticle

Additive Manufacturing Polyurethane Acrylate via Stereolithography for 3D Structure Polymer Electrolyte Application

by Muhammad Faishal Norjeli, Nizam Tamchek, Zurina Osman, Ikhwan Syafiq Mohd Noor, Mohd Zieauddin Kufian and Mohd Ifwat Bin Mohd Ghazali

Gels 2022, 8(9), 589; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8090589 - 15 Sep 2022

Cited by 9 | Viewed by 2024

Abstract

Additive manufacturing (AM), also known as 3D-printing technology, is currently integrated in many fields as it possesses an attractive fabrication process. In this work, we deployed the 3D-print stereolithography (SLA) method to print polyurethane acrylate (PUA)-based gel polymer electrolyte (GPE). The printed PUA [...] Read more.

Additive manufacturing (AM), also known as 3D-printing technology, is currently integrated in many fields as it possesses an attractive fabrication process. In this work, we deployed the 3D-print stereolithography (SLA) method to print polyurethane acrylate (PUA)-based gel polymer electrolyte (GPE). The printed PUA GPE was then characterized through several techniques, such as Fourier transform infrared (FTIR), electrochemical impedance spectroscopy (EIS), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM). The printed GPE exhibited high ionic conductivity of 1.24 × 10⁻³ S cm⁻¹ at low-lithium-salt content (10 wt.%) in ambient temperature and favorable thermal stability to about 300 °C. The FTIR results show that addition of LiClO₄ to the polymer matrix caused a shift in carbonyl, ester and amide functional groups. In addition, FTIR deconvolution peaks of LiClO₄ show 10 wt.% has the highest amount of free ions, in line with the highest conductivity achieved. Finally, the PUA GPE was printed into 3D complex structure to show SLA flexibility in designing an electrolyte, which could be a potential application in advanced battery fabrication. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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12 pages, 2649 KiB

Open AccessArticle

Collagen Matrices Mediate Glioma Cell Migration Induced by an Electrical Signal

by Li Yao, Kimmy Tran and Diana Nguyen

Gels 2022, 8(9), 545; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8090545 - 29 Aug 2022

Cited by 2 | Viewed by 1558

Abstract

Glioma cells produce an increased amount of collagen compared with normal astrocytes. The increasing amount of collagen in the extracellular matrix (ECM) modulates the matrix structure and the mechanical properties of the microenvironment, thereby regulating tumor cell invasion. Although the regulation of tumor [...] Read more.

Glioma cells produce an increased amount of collagen compared with normal astrocytes. The increasing amount of collagen in the extracellular matrix (ECM) modulates the matrix structure and the mechanical properties of the microenvironment, thereby regulating tumor cell invasion. Although the regulation of tumor cell invasion mainly relies on cell–ECM interaction, the electrotaxis of tumor cells has attracted great research interest. The growth of glioma cells in a three-dimensional (3D) collagen hydrogel creates a relevant tumor physiological condition for the study of tumor cell invasion. In this study, we tested the migration of human glioma cells, fetal astrocytes, and adult astrocytes in a 3D collagen matrix with different collagen concentrations. We report that all three types of cells demonstrated higher motility in a low concentration of collagen hydrogel (3 mg/mL and 5 mg/mL) than in a high concentration of collagen hydrogel (10 mg/mL). We further show that human glioma cells grown in collagen hydrogels responded to direct current electric field (dcEF) stimulation and migrated to the anodal pole. The tumor cells altered their morphology in the gels to adapt to the anodal migration. The directedness of anodal migration shows a field strength-dependent response. EF stimulation increased the migration speed of tumor cells. This study implicates the potential role of an dcEF in glioma invasion and as a target of treatment. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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15 pages, 3162 KiB

Open AccessArticle

Transforming Capillary Alginate Gel (Capgel) into New 3D-Printing Biomaterial Inks

by Andrew Philip Panarello, Corey Edward Seavey, Mona Doshi, Andrew K. Dickerson, Thomas J. Kean and Bradley Jay Willenberg

Gels 2022, 8(6), 376; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8060376 - 14 Jun 2022

Cited by 4 | Viewed by 2866

Abstract

Three-dimensional (3D) printing has great potential for creating tissues and organs to meet shortfalls in transplant supply, and biomaterial inks are key components of many such approaches. There is a need for biomaterial inks that facilitate integration, infiltration, and vascularization of targeted 3D-printed [...] Read more.

Three-dimensional (3D) printing has great potential for creating tissues and organs to meet shortfalls in transplant supply, and biomaterial inks are key components of many such approaches. There is a need for biomaterial inks that facilitate integration, infiltration, and vascularization of targeted 3D-printed structures. This study is therefore focused on creating new biomaterial inks from self-assembled capillary alginate gel (Capgel), which possesses a unique microstructure of uniform tubular channels with tunable diameters and densities. First, extrusions of Capgel through needles (0.1–0.8 mm inner diameter) were investigated. It was found that Capgel ink extrudes as slurries of fractured and entangled particles, each retaining capillary microstructures, and that extruded line widths W and particle sizes A were both functions of needle inner diameter D, specifically power-law relationships of W~D^0.42 and A~D^1.52, respectively. Next, various structures were successfully 3D-printed with Capgel ink, thus demonstrating that this biomaterial ink is stackable and self-supporting. To increase ink self-adherence, Capgel was coated with poly-L-lysine (PLL) to create a cationic “skin” prior to extrusion. It was hypothesized that, during extrusion of Capgel-PLL, the sheared particles fracture and thereby expose cryptic sites of negatively-charged biomaterial capable of forming new polyelectrolyte bonds with areas of the positively-charged PLL skin on neighboring entangled particles. This novel approach resulted in continuous, self-adherent extrusions that remained intact in solution. Human lung fibroblasts (HLFs) were then cultured on this ink to investigate biocompatibility. HLFs readily colonized Capgel-PLL ink and were strongly oriented by the capillary microstructures. This is the first description of successful 3D-printing with Capgel biomaterial ink as well as the first demonstration of the concept and formulation of a self-adherent Capgel-PLL biomaterial ink. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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14 pages, 4395 KiB

Open AccessArticle

Supramolecular Rings as Building Blocks for Stimuli-Responsive Materials

by Hanna Traeger, Alyssa Ghielmetti, Yoshimitsu Sagara, Stephen Schrettl and Christoph Weder

Gels 2022, 8(6), 350; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8060350 - 03 Jun 2022

Viewed by 2004

Abstract

Stimuli-responsive polymers are of great interest due to their ability to translate changing environmental conditions into responses in defined materials. One possibility to impart such behavior is the incorporation of optically active molecules into a polymer host. Here, we describe how sensor molecules [...] Read more.

Stimuli-responsive polymers are of great interest due to their ability to translate changing environmental conditions into responses in defined materials. One possibility to impart such behavior is the incorporation of optically active molecules into a polymer host. Here, we describe how sensor molecules that consist of a π-extended benzothiadiazole emitter and a naphthalene diimide quencher can be exploited in this context. The two optically active entities were connected via different spacers and, thanks to attractive intramolecular interactions between them, the new sensor molecules assembled into cyclic structures in which the fluorescence was quenched by up to 43% when compared to solutions of the individual dyes. Detailed spectroscopic investigations of the sensor molecules in solution show that the extent of donor/acceptor interactions is influenced by various factors, including solvent polarity and ion concentration. The new sensor molecule was covalently incorporated into a polyurethane; the investigation of the optical characteristics in both the solid and solvent-swollen states indicates that a stimulus-induced formation of associated dye pairs is possible in polymeric materials. Indeed, a solvatochromic quenching effect similar to the behavior in solution was observed for solvent-swollen polymer samples, leading to an effective change of the green emission color of the dye to a yellow color. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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13 pages, 3101 KiB

Open AccessArticle

Fracture Toughness and Blocking Force of Temperature-Sensitive PolyNIPAAm and Alginate Hybrid Gels

by Yong-Woo Kim, Do Yoon Kim and Jeong-Yun Sun

Gels 2022, 8(5), 324; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8050324 - 23 May 2022

Cited by 5 | Viewed by 2586

Abstract

In the field of actuator materials, hydrogels that undergo large volume changes in response to external stimuli have been developed for a variety of promising applications. However, most conventional hydrogels are brittle and therefore rupture when they are stretched to moderate strains (~50%). [...] Read more.

In the field of actuator materials, hydrogels that undergo large volume changes in response to external stimuli have been developed for a variety of promising applications. However, most conventional hydrogels are brittle and therefore rupture when they are stretched to moderate strains (~50%). Thus, gels to be used for actuators still require improved mechanical properties and actuation performance. In this study, we synthesized a tough and thermo-sensitive hydrogel with a large actuation force by forming interpenetrating networks between covalently crosslinked poly(N-isopropylacrylamide) and ionically crosslinked alginate. Poly(N-isopropylacrylamide) was used as a thermo-sensitive actuation material, and alginate was found to enhance the mechanical properties of the hydrogels. Due to the enhanced elastic modulus and energy dissipation in the hybrid gel, the toughness was increased by a factor of 60 over that of pure PNIPAAm gel. Further, based on the results showing that the hybrid gel exhibits an actuation force that is seven times higher than that of pure PNIPAAm gel, the hybrid gel is more applicable to real actuators. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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11 pages, 2169 KiB

Open AccessArticle

Fabrication of Self-Oscillating Gels by Polymer Crosslinking Method and Analysis on Their Autonomous Swelling-Deswelling Behaviors

by Komi Sato, Takafumi Enomoto, Aya M. Akimoto and Ryo Yoshida

Gels 2022, 8(5), 267; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8050267 - 24 Apr 2022

Cited by 2 | Viewed by 2151

Abstract

We have developed a new methodology for fabricating self-oscillating gels by a post-polymerization crosslinking. The method enables us to make the self-oscillating gels easily just by mixing two kinds of polymer solutions at room temperature with fast gelation. Moreover, the polymer crosslinking method [...] Read more.

We have developed a new methodology for fabricating self-oscillating gels by a post-polymerization crosslinking. The method enables us to make the self-oscillating gels easily just by mixing two kinds of polymer solutions at room temperature with fast gelation. Moreover, the polymer crosslinking method has the advantage that the self-oscillating gels could be fabricated from well-defined linear polymers. We revealed that the dynamic swelling-deswelling behavior of the gels was simply affected by the net amount of the catalyst for the Belousov–Zhabotinsky reaction in the whole gels, although the equilibrium swelling behavior was influenced by the properties of the constituent linear polymers. Our results offer the opportunity to access the origin of the dynamic and equilibrium behavior of materials by the hierarchical assembly as well as enable easy microfabrication of the self-oscillating gel. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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24 pages, 26365 KiB

Open AccessArticle

Effect of Functional Group on the Catalytic Activity of Lipase B from Candida antarctica Immobilized in a Silica-Reinforced Pluronic F127/α-Cyclodextrin Hydrogel

by Cédric Decarpigny, Anne Ponchel, Eric Monflier and Rudina Bleta

Gels 2022, 8(1), 3; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8010003 - 21 Dec 2021

Cited by 3 | Viewed by 2306

Abstract

Surface modification plays a key role in the fabrication of highly active and stable enzymatic nanoreactors. In this study, we report for the first time the effect of various functional groups (epoxy, amine, trimethyl, and hexadecyl) on the catalytic performance of lipase B [...] Read more.

Surface modification plays a key role in the fabrication of highly active and stable enzymatic nanoreactors. In this study, we report for the first time the effect of various functional groups (epoxy, amine, trimethyl, and hexadecyl) on the catalytic performance of lipase B from Candida antarctica (CALB) incorporated within a monolithic supramolecular hydrogel with multiscale pore architecture. The supramolecular hydrogel formed by host-guest interactions between α-cyclodextrin (α-CD) and Pluronic F127 was first silicified to provide a hierarchically porous material whose surface was further modified with different organosilanes permitting both covalent anchoring and interfacial activation of CALB. The catalytic activity of nanoreactors was evaluated in the liquid phase cascade oxidation of 2,5-diformylfuran (DFF) to 2,5-furandicarboxylic acid (FDCA) under mild conditions. Results showed that high FDCA yields and high efficiency conversion of DFF could be correlated with the ability of epoxy and amine moieties to keep CALB attached to the carrier, while the trimethyl and hexadecyl groups could provide a suitable hydrophobic-hydrophilic interface for the interfacial activation of lipase. Cationic cross-linked β-CD was also evaluated as an enzyme-stabilizing agent and was found to provide beneficial effects in the operational stability of the biocatalyst. These supramolecular silicified hydrogel monoliths with hierarchical porosity may be used as promising nanoreactors to provide easier enzyme recovery in other biocatalytic continuous flow processes. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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Review

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17 pages, 1483 KiB

Open AccessReview

Intelligent Hydrogels in Myocardial Regeneration and Engineering

by Christian Doescher, An Thai, Ed Cha, Pauline V. Cheng, Devendra K. Agrawal and Finosh G. Thankam

Gels 2022, 8(9), 576; https://0-doi-org.brum.beds.ac.uk/10.3390/gels8090576 - 09 Sep 2022

Cited by 4 | Viewed by 2209

Abstract

Myocardial infarction (MI) causes impaired cardiac function due to the loss of cardiomyocytes following an ischemic attack. Intelligent hydrogels offer promising solutions for post-MI cardiac tissue therapy to aid in structural support, contractility, and targeted drug therapy. Hydrogels are porous hydrophilic matrices used [...] Read more.

Myocardial infarction (MI) causes impaired cardiac function due to the loss of cardiomyocytes following an ischemic attack. Intelligent hydrogels offer promising solutions for post-MI cardiac tissue therapy to aid in structural support, contractility, and targeted drug therapy. Hydrogels are porous hydrophilic matrices used for biological scaffolding, and upon the careful alteration of ideal functional groups, the hydrogels respond to the chemistry of the surrounding microenvironment, resulting in intelligent hydrogels. This review delves into the perspectives of various intelligent hydrogels and evidence from successful models of hydrogel-assisted treatment strategies. Full article

(This article belongs to the Special Issue Functional Transformations in Polymer Gels)

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