Polymer Hydrogels Research Articles

Intestinal-Target and Glucose-Responsive Smart Hydrogel toward Oral Delivery System of Drug with Improved Insulin Utilization.

An intelligent insulin delivery system targeting intestinal absorption and glucose responsiveness can enhance the bioavailability through oral insulin therapy, offering promising diabetes treatment. In this paper, a glucose and pH dual-response polymer hydrogel using carboxymethyl agarose modified with 3-amino-phenylboronic acid and l-valine (CPL) was developed as an insulin delivery carrier, exhibiting excellent biocompatibility and effective insulin encapsulation. The insulin encapsulated in the hydrogel (Ins-CPL) was released in a controlled manner in response to the in vivo stimulation of blood glucose and pH levels with higher levels of intracellular uptake and utilization of insulin in the intestinal environment simultaneously. Notably, the Ins-CPL hydrogel effectively regulated blood sugar in diabetic rats over a long period by simulating endogenous insulin, responding to changes in plasma pH and glucose levels, and overcoming the intestinal epithelium barrier. This indicates a significant boost in oral insulin bioavailability and broadens its application prospects.

High-Strength PVA/Cellulosic hydrogels with Acid/Base and thermo dual-responsive fluorescence

Fluorescent polymer hydrogels (FPHs) with tunable luminous features have attracted immense interest. Nevertheless, until now, the development of most FPHs had been hindered by their poor mechanical properties and limited application range. This study presents a novel strategy to fabricate high-strength, multi-application cellulosic fluorescent hydrogels using polyvinyl alcohol (PVA) and fluorescent nanocellulose (containing pyrene tetracarboxylic acid) through a salting-out process. Such strategy enables cellulosic hydrogels with high tensile strength and toughness (26.45 MPa and 201.27 MJ/m3), compressive strength (165.58 MPa), dual-responsive fluorescence (acid/base and temperature), and multiple applications. Specifically, cellulosic hydrogels exhibit fluorescence switching through the utilization of lanthanide metals (Eu3+/Tb3+), acid/base, and temperature, owing to the presence of perylene tetracarboxylic acid as a fluorescent moiety with an aggregation-caused quenching (ACQ) effect. Based on this, the resulting hydrogels were utilized in rewritable display systems, temperature monitoring, and encrypted QR codes. This study envisions opening new possibilities for the development of high-strength fluorescent hydrogels with multiple applications.

Synthesis and Characterization of cellulose-derived superabsorbent hydrogel and its applications in the treatment of wastewater containing heavy metal ions

A cellulose xanthate (CX) based polymer hydrogel has been synthesized using free radical graft polymerization technique. Two monomers Acrylic Acid (AA) and Acrylonitrile (AN) were reacted with cellulose xanthate to synthesize the desired hydrogel CX-g-poly(AA-co-AN). The synthesized hydrogel has been characterized by various techniques viz. Thermo-gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV), Field emission scanning electron microscope (FESEM) and Point zero charge (PZC). This hydrogel has been employed for the removal of toxic metal ions from wastewater. The maximum percentage removal has been found to be 97.5 (±4.87)% for Cu2+ ions and 96.1 (±4.80)% for Co2+ ions under optimum pH 6. The calculated adsorption capacities have been found to be 330.03 (±35.3) mg/g for Cu2+ ions and 325.73 (±22.4) mg/g for Co2+ ions using the Langmuir Adsorption isotherm model. The thermodynamic parameters depicted that the process was endothermic, and spontaneous. The adsorption kinetics data shows excellent fit with pseudo-second-order kinetic model. The synthesized hydrogel exhibits a high swelling ratio of 846.85 (±42.36) g/g and retention ratio of 50.12 (±2.50) % in distilled water. Also, the synthesized hydrogel showed good reusability, exhibiting percentage removal 83.2% for Cu2+ ions and 81.3% for Co2+ ions in the fifth cycle.

Development of Malate Biosensor-Containing Hydrogels and Living Cell-Based Sensors.

Malate is a key intermediate in the citric acid cycle, an enzymatic cascade that is central to cellular energy metabolism and that has been applied to make biofuel cells. To enable real-time sensing of malate levels, we have engineered a genetically encoded, protein-based fluorescent biosensor called Malon specifically responsive to malate by performing structure-based mutagenesis of the Cache-binding domain of the Citron GFP-based biosensor. Malon demonstrates high specificity and fluorescence activation in response to malate, and has been applied to monitor enzymatic reactions in vitro. Furthermore, we successfully incorporated Malon into redox polymer hydrogels and bacterial cells, enabling analysis of malate levels in these materials and living systems. These results show the potential for fluorescent biosensors in enzymatic cascade monitoring within biomaterials and present Malon as a novel tool for bioelectronic devices.

Utilizing acrylic acid polymer hydrogel for 3-D quality assurance in CyberKnife radiotherapy

Dosimetry tools play a crucial role in radiotherapy as they are essential for recording and validating intricate 3-D dose distributions. This research introduces and examines a novel acrylic acid polymer hydrogel (ACAPHG) dosimeter composition designed for 3-D dose verification and quality assurance in the context of radiotherapy treatment. A phantom made of an 80 mm diameter cylindrical glass container was utilized. The phantom contained the hydrogel, which served as the medium for radiation exposure. The water equivalent hydrogel within the phantom was subjected to irradiation by a CyberKnife robotic radiotherapy system. An optical computed tomography (OCT) scanner with sub-millimeter resolution was used to obtain imaging data. The dose distribution of a CyberKnife robotic SRS/SBRT treatment plan for a brain cancer patient was compared to that of the hydrogel's OCT scan using 2-D and 3-D gamma analysis with a criterion of 3% dose difference and 3 mm distance-to-agreement. A gamma pass rate of 94.1% for the 2-D gamma analysis and a pass rate of 99% for the 3-D gamma analysis were calculated within the region at which the treatment planning system data drops to 20% of the maximum dose. The use of the ACAPHG dosimeter in conjunction with the described setup suggests that it has the potential to offer an accurate 3-D verification of complex dose distributions in SRS/SBRT radiotherapy treatments. By employing the ACAPHG dosimeter and utilizing OCT scanning, this dosimeter enables the assessment and validation of intricate dose distributions in these advanced radiotherapy treatments.

High-Performance Dual-Redox-Mediator Supercapacitors Based on Buckypaper Electrodes and Hydrogel Polymer Electrolytes.

In recent years, the demand for solid, thin, and flexible energy storage devices has surged in modern consumer electronics, which require autonomy and long duration. In this context, hybrid supercapacitors have become strategic, and significant efforts are being made to develop cells with higher energy densities while preserving the power density of conventional supercapacitors. Motivated by these requirements, we report the development of a new high-performance dual-redox-mediator supercapacitor. In this study, cells were constructed using fully moldable buckypapers (BPs), composed of carbon nanotubes and cellulose nanofibers, as electrodes. We evaluated the compatibility of BPs with hydrogel polymer electrolytes, based on 1 mol L-1 H2SO4 and polyvinyl alcohol (PVA), supplemented with different redox species: methylene blue, indigo carmine, and hydroquinone. Solid cells were constructed containing two active redox species to maximize the specific capacity of each electrode. Considering the main results, the dual-redox-mediator supercapacitor exhibits high energy density of 32.0 Wh kg-1 (at 0.8 kW kg-1) and is capable of delivering 25.9 Wh kg-1 at high power demand (4.0 kW kg-1). Stability studies conducted over 10,000 galvanostatic cycles revealed that the PVA polymer matrix benefits the system by inhibiting the crossover of redox species within the cell.

Nonuniversal Dynamics of Hyperbranched Metallo-Supramolecular Polymer Networks by the Spontaneous Formation of Nanoparticles.

Various transient and permanent bonds are commonly combined in increasingly complex hierarchical structures to achieve biomimetic functions, along with high mechanical properties. However, there is a traditional trade-off between mechanical strength and biological functions like self-healing. To fill this gap, we develop a metallo-supramolecular polymer hydrogel based on the hyperbranched poly(ethylene imine) (PEI) backbone and phenanthroline ligands, which have unexpectedly high plateau modulus at low concentrations. Rheological measurements demonstrate nonuniversal metal-ion-specific dynamics, with significantly larger plateau moduli, longer relaxation times, and stronger temperature dependencies, compared to equivalent networks based on model-type telechelic precursors, which cannot be explained by the theory of linear viscoelasticity. TEM images reveal the in situ mineralization of metal ions, which nucleate by the ligand complexation and grow thanks to the spontaneous reducing effect of the PEI backbone. Evidently, the complex lifetime works against Ostwald ripening, resulting in the formation of thermodynamically stable smaller particles. This trend is followed by time-dependent network buildup measurements and is confirmed by a kinetic model for particle formation and aggregation. The spontaneous formation of particles with complex lifetime-dependent sizes can explain the nonuniversal dynamics through the interaction of polymer segments and particles at the nanoscale. This work describes how the polymer backbone can affect the strength and stability of supramolecular bonds, promising for combining high mechanical properties and self-healing comparable to natural tissues.

Sustained release of proteins from contact lenses with porous annulus.

Ophthalmic drugs are administered to the front of the eye by eyedrops. The bioavailability of drugs delivered via eye drops is low due to tear turnover. Contact lenses can address some deficiencies of eye drops by sustaining the delivery of drugs, but commercial contact lenses have small pore sizes that cannot load biologics, which are becoming more common for treating ophthalmic diseases. This study aims to investigate novel poly(hydroxyethyl methacrylate) (pHEMA) lenses with transparent center and porous annulus for sustained release of model proteins. A novel hydrogel polymerization process was used to fabricate concentric, porous layer pHEMA hydrogel rods. The hydrogels were lathe cut into contact lenses which were explored for the delivery of proteins and gold nanoparticles. Lenses were characterized by partition coefficient and diffusivity, which was estimated by fitting experimental data to an analytical model. Transmittance measurements were made to compare transparency of porous lens centers to commercial contact lenses. Porous pHEMA lenses consisting of a concentric, porous layer made from 55% water content in precursor were successfully lathe cut into lenses with transparent center and opaque porous annulus. The porous lenses could load large model proteins of bovine serum albumin and human γ-globulin and provide sustained release. The core annular pHEMA contact lenses consisting of an outer annulus of opaque, porous pHEMA and an inner, center layer of clear, nonporous pHEMA can provide sustained delivery of biologics.

Marine Amoebae‐Inspired Salting Hydrogels to Reconfigure Anisotropy for Reprogrammable Shape Morphing

Reprogrammable shape morphing is ubiquitous in living beings and highly crucial for them to move in normal situations, even to survive under dangerous conditions. There is increasing interest in using asymmetric hydrogel structures to understand and mimic living beings’ shape morphing upon an external trigger in a controlled way. However, these asymmetric or heterogeneous configurations cannot be further modified once the polymer hydrogels are prepared. Therefore, it is a great challenge to achieve reprogrammable shape morphing using the existing hydrogels. Inspired by marine amoebae, which transform into several different morphologies according to the various external salt concentrations, a new strategy is developed for salting hydrogels to reconfigure their anisotropy toward reprogrammable shape morphing. Polyampholyte hydrogels with equal stoichiometric COO‒ and N+(CH3)3 groups were first swollen in HCl/NaCl solution. After being then transferred into water, they first swollen again by water uptake driven by the osmotic pressure, and then were spontaneously deswollen due to increase in internal pH and dialysis of ions leading to deprotonation of COOH to COO‒ and regeneration of COO‒/N+(CH3)3 electrostatic attraction. This work provides a novel strategy to reconfigure anisotropy of hydrogel soft actuators and to open up an avenue for reprogrammable shape morphing.

Marine Amoebae-Inspired Salting Hydrogels to Reconfigure Anisotropy for Reprogrammable Shape Morphing.

Reprogrammable shape morphing is ubiquitous in living beings and highly crucial for them to move in normal situations, even to survive under dangerous conditions. There is increasing interest in using asymmetric hydrogel structures to understand and mimic living beings' shape morphing upon an external trigger in a controlled way. However, these asymmetric or heterogeneous configurations cannot be further modified once the polymer hydrogels are prepared. Therefore, it is a great challenge to achieve reprogrammable shape morphing using the existing hydrogels. Inspired by marine amoebae, which transform into several different morphologies according to the various external salt concentrations, a new strategy is developed for salting hydrogels to reconfigure their anisotropy toward reprogrammable shape morphing. Polyampholyte hydrogels with equal stoichiometric COO‒ and N+(CH3)3 groups were first swollen in HCl/NaCl solution. After being then transferred into water, they first swollen again by water uptake driven by the osmotic pressure, and then were spontaneously deswollen due to increase in internal pH and dialysis of ions leading to deprotonation of COOH to COO‒ and regeneration of COO‒/N+(CH3)3 electrostatic attraction. This work provides a novel strategy to reconfigure anisotropy of hydrogel soft actuators and to open up an avenue for reprogrammable shape morphing.

Hydrogel Films with Impact Resistance by Sacrificial Micelle-Assisted-Alignment.

Various strategies are developed to engineer aligned hierarchical architectures in polymer hydrogels for enhanced mechanical performance. However, chain alignment remains impeded by the presence of hydrogen bonds between adjacent chains. Herein, a facile sacrificial micelle-assisted-alignment strategy is proposed, leading to well-aligned, strong and tough pure chitosan hydrogels. The sacrificial sodium dodecyl sulfate micelles electrostatically interact with the protonated chitosan chains, enabling chain sliding and alignment under uniaxial forces. Subsequently, sacrificial micelles can be easily removed via NaOH treatment, causing the reforming of H-bond in the chain networks. The strength of the pure chitosan hydrogels increases 140-fold, reaching 58.9±3.4MPa; the modulus increases 595-fold, reaching 226.4±42.8MPa. After drying-rehydration, the strength and modulus further rise to 70.3±2.4 and 403.5±76.3MPa, marking a significant advancement in high-strength pure chitosan hydrogel films. Furthermore, the designed multiscale architectures involving enhanced crystallinity, well-aligned fibers, strong interfaces, robust multilayer Bouligand assembly contribute to the exact replica of lobster underbelly with impact resistance up to 6.8±1.0kJ m-1. This work presents a promising strategy for strong, tough, stiff and impact-resistant polymer hydrogels via well-aligned hierarchical design.

Injectable Hydrogel With Glycyrrhizic Acid and Asiaticoside-Loaded Liposomes for Wound Healing.

Open skin wounds increase the risk of infections and can compromise health. Therefore, applying medications to promote healing at the injury site is crucial. In practice, direct drug delivery is often difficult to maintain for a long time due to rapid absorption or wiping off, which reduces the efficiency of wound healing. Consequently, the development of bioactive materials with both antibacterial and wound-healing properties is highly desirable. This study synthesized liposomes loaded with glycyrrhizic acid (GA) and asiaticoside (AS) by film dispersion-ultrasonication method, which were then incorporated into a GelMA solution and cross-linked by ultraviolet light to form a bioactive composite hydrogel for wound dressings. This hydrogel is conducive to the transport of nutrients and gas exchange. Compared with GelMA hydrogel (swelling rate 69.8% ± 5.7%), the swelling rate of GelMA/Lip@GA@AS is lower, at 52.1% ± 1.0%. GelMA/Lip@GA@AS also has better compression and rheological properties, and the invitro biodegradability is not significantly different from that of the collagenase-treated group. In addition, the hydrogel polymer has a stable drug release rate, good biocompatibility, and an angiogenic promoting effect. Invitro experiments prove that, at concentrations of 0.5, 1, 2, and 3 mg/mL, GelMA/Lip@GA@AS can inhibit the growth of Staphylococcus aureus. We synthesized GelMA/Lip@GA@AS hydrogel and found it possesses advantageous mechanical properties, rheology, and biodegradability. Experimental results invitro showed that the bioactive hydrogel could efficiently release drugs, exhibit biocompatibility, and enhance angiogenesis and antimicrobial effects. These results suggest the promising application of GelMA/Lip@GA@AS hydrogel in wound-dressing materials.

Living Cell-Mediated Catalyst-Free Spontaneous Polymerization of Zwitterionic Methacrylates for Preparation of Probiotic-Loaded Hydrogels.

Living cell-mediated polymerization offers promising applications in biomaterials, yet its further biological utilization is hindered by the need for metal ions or radical initiators with available methods. In this study, we introduce a living cell-mediated polymerization that leverages the intrinsic metabolic activities of living cells to initiate and sustain free radical polymerization of zwitterionic methacrylates. The polymerization proceeded in the absence of transition metal catalysts, radical initiators, or light sources. The conversion of zwitterionic methacrylate strongly correlated with cellular activities and achieved a maximum conversion of 98% within 48 hours. Living cells efflux redox power across membranes through metabolism and that terminal electron fluxes are captured by zwitterionic methacrylates pre-assembled on the living cell surface to initiate radical polymerization reactions. The polymerization caused significant changes to the cell membrane surface and synthesized hydrogels with tailored mechanical properties. The polymer hydrogel obtained via probiotic E. coli Nissle 1917 was able to release the in-situ encapsulated molecules, which demonstrated living cell-mediated polymer hydrogel as a vehicle for the delivery of both cellular and molecular therapeutic agents. This research offered a green and efficient method for synthesizing bioactive materials and advancing the field of cellular therapeutics and drug delivery.

Living Cell‐Mediated Catalyst‐Free Spontaneous Polymerization of Zwitterionic Methacrylates for Preparation of Probiotic‐Loaded Hydrogels

Living cell‐mediated polymerization offers promising applications in biomaterials, yet its further biological utilization is hindered by the need for metal ions or radical initiators with available methods. In this study, we introduce a living cell‐mediated polymerization that leverages the intrinsic metabolic activities of living cells to initiate and sustain free radical polymerization of zwitterionic methacrylates. The polymerization proceeded in the absence of transition metal catalysts, radical initiators, or light sources. The conversion of zwitterionic methacrylate strongly correlated with cellular activities and achieved a maximum conversion of 98% within 48 hours. Living cells efflux redox power across membranes through metabolism and that terminal electron fluxes are captured by zwitterionic methacrylates pre‐assembled on the living cell surface to initiate radical polymerization reactions. The polymerization caused significant changes to the cell membrane surface and synthesized hydrogels with tailored mechanical properties. The polymer hydrogel obtained via probiotic E. coli Nissle 1917 was able to release the in‐situ encapsulated molecules, which demonstrated living cell‐mediated polymer hydrogel as a vehicle for the delivery of both cellular and molecular therapeutic agents. This research offered a green and efficient method for synthesizing bioactive materials and advancing the field of cellular therapeutics and drug delivery.

An optical system for cellular mechanostimulation in 3D hydrogels

We introduce a method utilizing single laser-generated cavitation bubbles to stimulate cellular mechanotransduction in dermal fibroblasts embedded within 3D hydrogels. We demonstrate that fibroblasts embedded in either amorphous or fibrillar hydrogels engage in Ca2+ signaling following exposure to an impulsive mechanical stimulus provided by a single 250 µm diameter laser-generated cavitation bubble. We find that the spatial extent of the cellular signaling is larger for cells embedded within a fibrous collagen hydrogel as compared to those embedded within an amorphous polyvinyl alcohol polymer (SLO-PVA) hydrogel. Additionally, for fibroblasts embedded in collagen, we find an increased range of cellular mechanosensitivity for cells that are polarized relative to the radial axis as compared to the circumferential axis. By contrast, fibroblasts embedded within SLO-PVA did not display orientation-dependent mechanosensitivity. Fibroblasts embedded in hydrogels and cultured in calcium-free media did not show cavitation-induced mechanotransduction; implicating calcium signaling based on transmembrane Ca2+ transport. This study demonstrates the utility of single laser-generated cavitation bubbles to provide local non-invasive impulsive mechanical stimuli within 3D hydrogel tissue models with concurrent imaging using optical microscopy. Statement of significanceCurrently, there are limited methods for the non-invasive real-time assessment of cellular sensitivity to mechanical stimuli within 3D tissue scaffolds. We describe an original approach that utilizes a pulsed laser microbeam within a standard laser scanning microscope system to generate single cavitation bubbles to provide impulsive mechanostimulation to cells within 3D fibrillar and amorphous hydrogels. Using this technique, we measure the cellular mechanosensitivity of primary human dermal fibroblasts embedded in amorphous and fibrillar hydrogels, thereby providing a useful method to examine cellular mechanotransduction in 3D biomaterials. Moreover, the implementation of our method within a standard optical microscope makes it suitable for broad adoption by cellular mechanotransduction researchers and opens the possibility of high-throughput evaluation of biomaterials with respect to cellular mechanosignaling.

Efficacy of a RADA-16 peptide hydrogel versus chitosan-based polymer in improving patient comfort during postoperative debridement: A randomized controlled trial.

Bioresorbable nasal packing is associated with a decreased incidence of adhesions and bleeding postoperatively after endoscopic sinus surgery (ESS). However, discomfort during postoperative debridement is still a major area of concern for patients. Our objective was to compare the efficacy of a peptide hydrogel to that of a chitosan-based polymer in reducing pain during debridement after ESS. A prospective, multicenter, randomized, blinded trial was conducted in adults undergoing bilateral total ethmoidectomy for chronic rhinosinusitis. Participants served as their own controls with each subject receiving the hydrogel in a randomized ethmoid cavity and chitosan-based polymer in the contralateral ethmoid cavity. Participants were evaluated at 1, 4, and 12weeks postoperatively. Pain during debridement as well as endoscopic evaluation of mucosal healing and hemostasis were measured. Thirty patients who underwent ESS were included in this trial. During the week 1 postoperative debridement, patients reported significantly less pain on the hydrogel-treated side compared to the chitosan-based polymer-treated side. There were no significant differences in bleeding severity, Lund-Kennedy scores, debridement time, or need for further intervention between the two groups. This study demonstrated the efficacy of a peptide hydrogel inminimizing pain during postoperative debridement.

Encapsulating Rhodamine 6G in Oxidized Sodium Alginate Polymeric Hydrogel for Photodynamically Inactivating Cancer Cells.

As cancer therapy progresses, challenges remain due to the inherent drawbacks of conventional treatments such as chemotherapy, gene therapy, radiation therapy, and surgical removal. Moreover, due to their associated side effects, conventional treatments affect both cancerous and normal cells, making photodynamic therapy (PDT) an attractive alternative. As a result of its minimal toxicity, exceptional specificity, and non-invasive characteristics, PDT represents an innovative and highly promising cancer treatment strategy using photosensitizers (PSs) and precise wavelength excitation light to introduce reactive oxygen species (ROS) in the vicinity of cancer cells. Poor aqueous solubility and decreased sensitivity of Rhodamine 6G (R6G) prevent its use as a photosensitizer in PDT, necessitating the development of oxidized sodium alginate (OSA) hydrogelated nanocarriers to enhance its bioavailability, targeted distribution, and ROS-quantum yield. The ROS quantum yield increased from 0.30 in an aqueous environment to 0.51 when using alginate-based formulations, and it was further enhanced to 0.81 in the case of OSA. Furthermore, the nanoformulations produced fluorescent signals suitable for use as cellular imaging agents, demonstrating contrast-enhancing capabilities in medical imaging and showing minimal toxicity.

Structure-Reactivity Relationships in a Small Library of Imine-Type Dynamic Covalent Materials: Determination of Rate and Equilibrium Constants Enables Model Prediction and Validation of a Unique Mechanical Softening in Dynamic Hydrogels.

The development of next generation soft and recyclable materials prominently features dynamic (reversible) chemistries such as host-guest, supramolecular, and dynamic covalent. Dynamic systems enable injectability, reprocessability, and time-dependent mechanical properties. These properties arise from the inherent relationship between the rate and equilibrium constants (RECs) of molecular junctions (cross-links) and the resulting macroscopic behavior of dynamic networks. However, few examples explicitly measure RECs while exploring this connection between molecular and material properties, particularly for polymeric hydrogel systems. Here we use dynamic covalent imine formation to study how single-point compositional changes in NH2-terminated nucleophiles affect binding constants and resulting hydrogel mechanical properties. We explored both model small molecule studies and model polymeric macromers, and found >3-decade change in RECs. Leveraging established relationships in the literature, we then developed a simple model to describe the cross-linking equilibrium and predict changes in hydrogel mechanical properties. Interestingly, we observed that a narrow ≈2-decade range of Keq's determine the bound fraction of imines. Our model allowed us to uncover a regime where adding cross-linker before saturation can decrease the cross-link density of a hydrogel. We then demonstrated the veracity of this predicted behavior experimentally. Notably this emergent behavior is not accounted for in covalent hydrogel theory. This study expands upon structure-reactivity relationships for imine formation, highlighting how quantitative determination of RECs facilitates predicting macroscopic behavior. Furthermore, while the present study focuses on dynamic covalent imine formation, the underlying principles of this work are applicable to the general bottom-up design of soft and recyclable dynamic materials.

Fabrication of GelMA - Agarose Based 3D Bioprinted Photocurable Hydrogel with In Vitro Cytocompatibility and Cells Mirroring Natural Keratocytes for Corneal Stromal Regeneration.

The complex anatomy of the cornea and the subsequent keratocyte-fibroblast transition have always made corneal stromal regeneration difficult. Recently, 3D printing has received considerable attentionin terms of fabrication of scaffoldswith precise dimension and pattern. In the current work, 3D printable polymer hydrogels made of GelMA/agarose are formulated and its rheological properties are evaluated. Despite the variation in agarose content, both the hydrogels exhibited G'>G'' modulus. A prototype for 3D stromal model is created using Solid Works software, mimicking the anatomy of an adult cornea. The fabrication of 3D-printed hydrogels is performed using pneumatic extrusion. The FTIR analysis speculated that the hydrogel is well crosslinked and established strong hydrogen bonding with each other, thus contributing to improved thermal and structural stability. The MTT analysis revealed a higher rate of cell proliferation on the hydrogels. The optical analysis carried out on the 14th day of incubation revealed that the hydrogels exhibit transparency matching with natural corneal stromal tissue. Specific protein marker expression confirmed the keratocyte phenotype and showed that the cells do not undergo terminal differentiation into stromal fibroblasts. The findings of this work point to the potential of GelMA/A hydrogels as a novel biomaterial for corneal stromal tissue engineering.

Inside Front Cover: Conducting polymer hydrogels based on supramolecular strategies for wearable sensors (EXP2 5/2024)

Inside Front Cover: Conducting polymer hydrogels based on supramolecular strategies for wearable sensors (EXP2 5/2024)