Polymer Hydrogels Research Articles

Laboratory synthesis and preparation of thermo-responsive polymeric micelle and hydrogel for resveratrol delivery and release

Laboratory synthesis and preparation of thermo-responsive polymeric micelle and hydrogel for resveratrol delivery and release

Prototyping sutureless shape-memory valve stent via integrated 3D printing

Abstract Transcatheter aortic valve replacement (TAVR) has increasingly emerged as a forefront option for treating aortic valve diseases. However, the currently prevalent valve prostheses used in TAVR typically involve stitching biologic leaflets onto metallic stents, which introduces challenges in the durability of leaflets and the biocompatibility of metallic stents. This work proposes an integrated additive manufacturing method for prototyping sutureless prosthetic aortic valves that combine shape memory polymer (SMP) stent and hydrogel valve leaflets. The SMP stent exhibits sufficient toughness to maintain structural integrity upon shape memory programming, while the Fe3+-treated hydrogel leaflets possess sufficient swelling resistance to ensure dimensional stability. Finally, the proof-of-concept valve stent is successfully fabricated by integrated 3D printing and validated via an in vitro hemodynamic experiment. Overall, our approach holds promise for prototyping sutureless polymeric valve stents for future generations.

TMIC-07. TRIPLE COCKTAIL IMMUNOMODULATION OF TUMOR DRAINING LYMPH NODES RESULTS IN SYNERGISTIC REVERSAL OF IMMUNOSUPPRESSION AND IMPROVED OVERALL SURVIVAL IN A MURINE GLIOBLASTOMA MODEL

Abstract Clinical trials involving anti-PD-1 fail to improve survival compared to standard of care in glioblastoma (GBM). Despite the advent of newer immunotherapies such as STING agonists and anti-CSF-1R, combination of these strategies is limited by necessitation of intracranial delivery (STING) or off-target side effects with systemic exposure (anti-CSF-1R + anti-PD-1). We have previously shown that delivery of anti-PD-1 to tumor draining lymph nodes via hydrogels decreases systemic exposure of anti-PD-1 and results in improved therapeutic response compared to systemic delivery. This study assesses the efficacy of combining STING agonist (STING), anti-CSF-1R (aCSF1r), and anti-PD-1 (aPD1) into a hydrogel nanoparticle that targets different components of immunosuppression in tumor draining lymph nodes. CT-2A murine glioma cells were orthotopically implanted into C57BL/6J mice with treatment on day 7 via deep cervical injection of hydrogel polymers loaded with either PBS (control), STING, aCSF1r, aPD1, or a combination of all three immunomodulators. Flow cytometry was used for immunophenotyping and Kaplan-Meier survival curves were generated to assess therapeutic efficacy. Each treatment strategy targeted a different component of immunosuppression. Compared to controls, aCSF1r resulted in the greatest decrease of immunosuppressive myeloid cells in the brain (P=0.0017) and cervical lymph nodes (P=0.0008); STING resulted in the greatest activation of intracranial dendritic cells (P=0.0001); and aPD1 resulted in the highest level of T cell activation of the monotherapies (P=0.0008) but also caused compensatory upregulation of regulatory T cells in the brain (P=0.0176). Combination therapy resulted in the greatest decrease in immunosuppression with increased T cell IFN-y production and dendritic cell activation, with resultant improvement in median and overall survival (P=0.0006). Triple combination therapy to tumor draining lymph nodes that specifically targets multiple components of immunosuppression is a safe and efficacious treatment that can be translated to clinical application.

Designing biphasic nanocellulose hydrogels to mimic the complex cartilage-bone interface

Osteochondral lesions, which affect both the cartilage and the bone, present significant challenges in treatment due to the complex mechanical and biochemical properties of these tissues. A crucial consideration in developing tissue replacements for these lesions is the simultaneous regeneration of cartilage and calcified cartilage, which forms the transition zone to bone. Our current study aims to fabricate a bilayer polymeric hydrogel designed not only to support cartilage regeneration but also to serve as an interface between cartilage and bone. The bilayer hydrogel was created by combining oxidized bacterial nanocellulose, gelatin, and alginate in one layer, while the other layer consisted of the same three biopolymers and hydroxyapatite. The bacterial nanocellulose was effectively oxidized (20%) with sodium periodate and then mineralized with calcium and phosphorus (Ca/P ratio = 0.97), as confirmed by EDX analysis. Remarkably, both layers of the biphasic hydrogel demonstrated cytocompatibility with chondrocytes. Moreover, the addition of hydroxyapatite significantly improved the mechanical strength from 72 kPa (OBC/Gel/Alg) to 90 kPa (MOBC/Gel/Alg). This bilayer hydrogel holds promise for promoting bone-cartilage integration and has the potential to contribute to the healing of osteochondral defects, offering new possibilities in the field of orthopedic tissue engineering and regenerative medicine.

Advanced Applications of Polymer Hydrogels in Electronics and Signal Processing

The current state of affairs in the field of using polymer hydrogels for the creation of innovative systems for signal and image processing, of which computing is a special case, is analyzed. Both of these specific examples of systems capable of forming an alternative to the existing semiconductor-based computing technology, but assuming preservation of the used algorithmic basis, and non-trivial signal converters, the nature of which requires transition to fundamentally different algorithms of data processing, are considered. It is shown that the variability of currently developed information processing systems based on the use of polymers, including polymer hydrogels, leads to the need to search for complementary algorithms. Moreover, the well-known thesis that modern polymer science allows for the realization of functional materials with predetermined properties, at the present stage, receives a new sounding: it is acceptable to raise the question of creating systems built on a quasi-biological basis and realizing predetermined algorithms of information or image processing. Specific examples that meet this thesis are considered, in particular, promising information protection systems for UAV groups, as well as systems based on the coupling of neural networks with holograms that solve various applied problems. These and other case studies demonstrate the importance of interdisciplinary cooperation for solving problems arising from the need for further modernization of signal processing systems.

Amphiphilic Gelator-Based Shear-Thinning Hydrogel for Minimally Invasive Delivery via Endoscopy Catheter to Remove Gastrointestinal Polyps.

Injectable polymeric hydrogels delivered via endoscopic catheter have emerged as promising submucosal agents, offering durable, long-lasting cushions to enhance the efficacy of endoscopic submucosal dissection (ESD) for the removal of small, flat polyps from the gastrointestinal tract (GIT). However, polymer-based injections do not meet the easy-injectability criteria via catheter because their high viscosity tends to clog the catheter needle. To the best of knowledge, for the first time, report the fabrication of an amphiphile-based small molecule hydrogel of diglycerol monostearate (DGMS)thatself-assembles to form hydrogel (DGMSH) for delivery via an endoscopic catheter. Physicochemical characterization of the hydrogel reveals its fibrous morphology, shear-thinning behaviour, and easy injectability, along with its scalability and long shelf-life (6 months). Ex vivo studies on the goat's stomach and intestine demonstrate the ease of injectability through the catheters and the development of visible submucosal cushion depots with the desired height. Moreover, the hydrogel can encapsulate both hydrophobic and hydrophilic drugs/dyes. In vivo studies in small animals have found that the hydrogel depot is durable, biocompatible, non-immunogenic, and has a hemostatic effect. Endoscopic studies in the porcine model demonstrate a safe injection and endoscopic excision of GI polyps acting as a suitable agent for ESD.

Silver Nanoparticle-Decorated Cellulose Nanocrystal Reinforced Ionic Polymer Hydrogel With High Conductivity and Environmental Tolerance for Multifunctional Sensing and Emergency Alarm System.

Conductive hydrogels hold great promise for flexible electronics. However, the simultaneous achievement of satisfactory mechanical strength, outstanding environmental tolerance, high sensitivity, and multiple sensing applications in a single conductive hydrogel remains a significant challenge. Herein, ionic polymer-based hydrogels with a double conductive network consisting of [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (DMC), 2-hydroxyethyl acrylate (HEA) and silver nanoparticle decorated cellulose nanocrystal (CNC@Ag) are prepared by a facile one-pot method. The resultant hydrogel (CDH) exhibits high stretchability, satisfactory self-adhesion, excellent environment tolerance (from -60 to 60°C), long-term stability (60 days), effective UV-shielding, and strong antibacterial properties. Significantly, the CDH hydrogel displays high conductivity and rapid response due to its double conductive network of ionic polymer and CNC@Ag. Therefore, the CDH-assembled sensor can accurately detect signals from both strain and pressure deformations, exhibiting outstanding sensitivity and reliability for human motion detection, signal transmission, object recognition, and tactile sensing. More interestingly, collaborating with a development board, the CDH-based sensor can be developed as an emergency alarm to realize prompt alarms in dangerous situations. Overall, this work presents a strategy for the fabrication of conductive hydrogel with remarkable properties, making it possible for multifunctional sensing applications in wearable electronics.

PH-sensitive polymeric hydrogels coated with cobalt ferrite nanoparticles for combined drug delivery as controlled release carriers: fabrication and in-vitro estimation

In this investigation, we produced pH-responsive hydrogels for the controlled release of drugs by graft copolymerizing Gum ghatti and acrylic acid (AA) in an aqueous medium. N, N′-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) served as cross-linkers during the synthesis process. Our research explores the integration of cobalt ferrite (CoFe2O4) magnetic nanoparticles (CFMNPs) in delivering a combination drug comprising metformin hydrochloride and sodium diclofenac. The diverse applications of CoFe2O4 nanoparticles have driven the exploration of innovative and environmentally sustainable production methods. The development of novel materials for nanoparticle synthesis adheres to the principles of “Green Chemistry” through a co-precipitation technique. Characterization of the cross-linked hydrogels involved Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analyses. In vitro drug release kinetics were observed under physiological conditions using Ultraviolet–Visible Spectroscopy. The drug-loaded Gg-cl-poly(AA)/CoFe2O4 hydrogels exhibited a sustained drug release profile over 24 h, with significant release occurring at a pH of 4. To comprehend the drug release mechanism, we employed kinetic modeling, encompassing Zero order, First order, Higuchi model, Hixson-Crowell model, and Korsmeyer-Peppas model, for all developed hydrogels. The findings indicated that the drug release mechanism from the hydrogels followed the Korsmeyer-Peppas model. The study concludes that the developed hydrogel offers a promising solution for the controlled administration of metformin hydrochloride and diclofenac sodium.Graphical

Conductive Biocomposite Made by Two-Photon Polymerization of Hydrogels Based on BSA and Carbon Nanotubes with Eosin-Y

Currently, tissue engineering technologies are promising for the restoration of damaged organs and tissues. For regeneration of electrically conductive tissues or neural interfaces, it is necessary to provide electrical conductivity for the transmission of electrophysiological signals. The developed biocomposite structures presented in this article possess such properties. Their composition includes bovine serum albumin (BSA), gelatin, eosin-Y and single-walled carbon nanotubes (SWCNTs). For the first time, a biocomposite structure was formed from the proposed hydrogel using a nanosecond laser, and a two-photon absorption cross section value of 580 GM was achieved. Increased viscosity over 3 mPa∙s and self-focusing with a nonlinear refractive index of 42 × 10−12 cm2/W make it possible to create a biocomposite structure over the entire specified area. The obtained electrical conductivity value was 19 mS∙cm−1, due to the formation of effective electrically conductive networks. For a biocomposite with a concentration of gelatin 3 wt. %, formed by low-energy near-IR pulses, the survival of Neuro 2A nerve tissue cells was confirmed. The obtained results are important for the creation of new tissue engineering structures and neural interfaces from a biopolymer hydrogel based on the organic dye eosin-Y and carbon nanotubes by two-photon polymerization.

Construction of an intelligent pH-sensitive hydrogel drug delivery system and its application in gastric ulcer treatment

The occurrence of gastric ulcer is mainly due to the damage of gastric mucosa which leads to inward flow of gastric acid to corrode the gastric cavity, thus producing gastric fever, vomiting, loss of appetite and other adverse reactions. Prevention and treatment of such injuries are crucial. In this study, a simple and non-toxic composite hydrogel (PLGA/CMCS) was prepared through Schiff base reaction between poly(lactic-co-glycolic acid) (PLGA) and carboxymethyl cellulose (CMCS). Subsequently, compound 1 was loaded onto it to construct PLGA/CMCS@1. A series of structural characterization and performance experiments were conducted on these novel hydrogel polymers. Furthermore, we detected the gene expression level of Fas/FasL apoptotic pathway after treating the cells with different concentrations of PLGA/CMCS@1 through an ethanol-induced damaged gastric mucosal epithelial cell model. The results showed that the system was able to significantly regulate the expression of genes related to the apoptotic pathway. The system can regulate the Fas/FasL apoptosis pathway to treat gastric ulcer.

Formulation of Asiatic acid-loaded polymeric chitosan-based hydrogel for effective MRSA infection control and enhanced wound healing in zebrafish models

BackgroundWound healing relies on a controlled inflammatory process vital for tissue regeneration. Chronic wounds, characterized by persistent inflammation and high infection risk, pose significant challenges in healthcare. Hydrogel dressings offer promise in wound care; however, the understanding of their role in managing inflammation and infection remains unclear. This study aimed to elucidate these processes and assess the efficacy of Asiatic acid (AA)-infused hydrogels in reducing inflammation and preventing infection. The unique properties of AA suggest its potential to modulate inflammation, promote tissue regeneration, and inhibit microbial colonization, thereby paving the way for specialized dressings that optimize healing outcomes. MethodsThe investigation encompassed the antibacterial, anti-biofilm, antioxidant activity, and biocompatibility of AA using a fibroblast cell line. A hydrogel incorporating AA was developed and characterized through scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), contact angle analysis, tensile testing, swelling capacity, and thermal stability assessments. Biodegradability was evaluated via enzymatic degradation, alongside controlled drug release and antibacterial efficacy against MRSA. In vivo studies using a zebrafish model examined wound healing and immune response. ResultsResults confirmed AA's potent antibacterial activity against MRSA and its effectiveness in disrupting mature biofilms. Additionally, AA exhibited strong antioxidant activity and biocompatibility. Morphological analysis revealed a pore structure conducive to wound healing, and the hydrogel demonstrated enhanced tensile strength, swelling properties, and thermal stability. In vivo, the AA-infused hydrogel accelerated wound closure, re-epithelialization, and immune response, supporting its potential for advanced wound care applications. In conclusion, the AA-infused chitosan hydrogel emerges as a promising candidate for advanced wound care therapies.

Additively Manufactured 3D Clamp-Culture System for the Investigation of Material-Cell Interactions in Multi-Material Hybrid Scaffolds for Musculoskeletal Tissue Defects.

The emergence of hybrid scaffolds, blending biomaterials with diverse properties, offers promise in musculoskeletal tissue engineering. However, a need for invitro platforms investigating biological behavior and the interplay of different load-bearing and colonizable synthetic bone substitute materials remains. Herein, we present a novel, in-house producible, and scalable clamp culture system designed for facile invitro analysis of interactions between biomaterials, hydrogels, and cells. The system, constructed here from an exemplary 3D-printable polymer and photopolymerizable hydrogel using a widely available benchtop 3D printer, ensures mechanical stability and protection for the embedded hydrogel via its double-clamp structure, facilitating various analytical methods while preserving culture integrity. Hybrid clamp cultures were additively manufactured from polylactic acid, filled with a bone precursor cell-laden methacrylate gelatin hydrogel, cultured for 14 days, and analyzed for cell viability, mineralization, and osseous differentiation. Results indicate no adverse effects on osteogenic differentiation or mineralization compared to conventional droplet cultures, with enhanced cell viability and simplified handling and downstream analysis. This system demonstrates the potential for robust experimentation in tissue engineering and is adaptable to various plate formats, and thus highly suitable for the investigation of biomaterial-cell interactions and the development of implants for musculoskeletal tissue defects.

Experimental study on fire extinguishing efficiency of polymer hydrogel fire extinguishing agent in pine-fir mixed coniferous forest fires

Experimental study on fire extinguishing efficiency of polymer hydrogel fire extinguishing agent in pine-fir mixed coniferous forest fires

Enzyme Activity Inhibition of α-Amylase Using Molecularly Imprinted Polymer (MIP) Hydrogel Microparticles.

Molecularly imprinted polymers (MIPs) are a class of synthetic recognition materials that offer a cost-effective and robust alternative to antibodies. While MIPs have found predominant use in biosensing and diagnostic applications, their potential for alternative uses, such as enzyme inhibition, remains unexplored. In this work, we synthesized a range of acrylamide-based hydrogel MIP microparticles (35 μm) specific for the recognition of α-amylase. These MIPs also showed good selectivity toward the target protein with over 96% binding of the target protein, compared with the control nonimprinted polymer (NIP) counterparts. Specificity of the MIPs was determined with the binding of nontarget proteins, trypsin, human serum albumin (HSA), and bovine serum albumin (BSA). The MIPs were further evaluated for their ability to inhibit α-amylase enzymatic activity, showing a significant decrease in activity. These findings highlight the potential of MIPs as enzyme inhibitors, suggesting an innovative application beyond their conventional use.

Model-based design of a mechanically intelligent shape-morphing structure

Soft robotics has significant interest within the industrial applications due to its advantages in flexibility and adaptability. Nevertheless, its potential is challenged by low stiffness and limited deformability, particularly in large-scale application scenarios such as underwater and offshore engineering. The integration of smart materials and morphing structures presents a promising avenue for enhancing the capabilities of soft robotic systems, especially in large deformation and variations in stiffness. In this study, we propose a multiple smart materials based mechanically intelligent structure devised through a model-based design framework. Specifically, the intelligent structure incorporates smart hydrogel and shape memory polymer (SMP). Employing the finite element method (FEM), we simulated the complex interactions among smart material to analyze the performance characteristics of the intelligent structure. The results demonstrate that, utilizing smart hydrogel and shape memory polymer (SMP) can effectively attain large deformation and exhibit variable stiffness due to the shape memory effect. Besides, the shape-morphing structures exhibit customized behaviours including bending, curling, and elongation, all while reducing reliance on external power sources. In conclusion, utilizing multiple smart materials within the model-based design framework offers an efficient approach for developing mechanically intelligent structure capable of complex deformations and variable stiffness, thereby providing support for underwater or offshore engineering applications.

Application of polymer adhesive hydrogel in wound healing

As the global adhesive industry continues to grow, researchers are discovering that polymer adhesives are playing an increasing role in the medical field, polymer adhesives have attracted more and more attention from the medical industry due to their unique advantages, such as hydrogels, have gradually appeared, which can effectively help wound healing. Most of the hydrogels have good biocompatibility and water absorption, and have the advantages of controllable structure, adjustable performance and easy degradation. Compared with traditional wound healing methods, hydrogels effectively reduce additional trauma and leakage and allow for greater tissue integration. This paper reviews the types of polymeric adhesive hydrogels and examples of some of them being artificially modified to be applied to the field of wound healing. Analyzes their mechanism of action and the advantages and shortcomings of their clinical applications, and finally looks into the potential functions and clinical efficacy of hydrogels in the future.

3D Printable Alginate-Chitosan Hydrogel Loaded With Ketoconazole Exhibits Anticryptococcal Activity.

Natural polymers have recently been investigated for various applications, such as 3D printing and healthcare, including treating infections. Among microbial infections, fungal diseases remain overlooked, with limited therapeutic options and high recurrence. Cutaneous cryptococcosis is an opportunistic fungal infection triggered by mechanical inoculation or hematogenous dissemination of the yeast that causes cryptococcal pneumonia and meningitis. Every year, Cryptococcus neoformans endanger the lives of immunosuppressed hosts, resulting in 180,000 deaths per year. Nonetheless, healthy individuals can also be affected by this fungal infection. Cryptococcosis has a restricted and expensive therapeutic regimen with no topical approach to skin manifestations. This study sought to create a 3D printable biodegradable polymeric hydrogel carrying ketoconazole, a low-cost antifungal drug with reported anticryptococcal activity. The developed hydrogel exhibited good 3D printability and rheological properties, including a pseudoplastic behavior. The FTIR spectra of cross-linked hydrogels revealed interactions between alginate and Ca+2, referred to as the egg-box model, indicated by the decrease in peaks at 1600 and 1410 cm-1. Furthermore, the hydrogel loaded with ketoconazole showed remarkable antifungal activity against C. neoformans strains indicated by inhibition zones, which cross-linking did not seem to affect its antifungal performance. The developed material remained structurally stable for up to 12 days (288 h) in swelling studies, and preliminary cytotoxicity performed with V79 cells indicates potential for invivo studies and topical application.

H2S-Eluting Hydrogels Promote In Vitro Angiogenesis and Augment In Vivo Ischemic Wound Revascularization

Ischemic wounds are frequently encountered in clinical practice and may be related to ischemia secondary to diabetes, peripheral artery disease and other chronic conditions. Angiogenesis is critical to the resolution of ischemia. Hydrogen sulfide (H2S) is now recognized as an important factor in this process. H2S donors NaHS and GYY4137 were incorporated into the photosensitive polymer hydrogel gelatin methacrylate and evaluated. Human umbilical vein endothelial cell (HUVEC) culture was used to quantify toxicity and angiogenesis. Sprague Dawley rats were subjected to ischemic myocutaneous flap wound creation with and without application of H2S-eluting hydrogels. Tissue perfusion during wound healing was quantified using laser speckle contrast imaging, and gene and protein expression for VEGF were evaluated. Vascular density was assessed by CD31 immunohistochemistry. Successful incorporation of sulfide compounds was confirmed by scanning electron microscopy with energy-dispersive X-ray analysis, and under physiologic conditions, detectable H2S was present for up to 14 days by high-performance liquid chromatography. HUVECs exposed to hydrogels did not demonstrate excess cytotoxicity or apoptosis. A two-fold increase in angiogenic tube formation was observed in HUVECs exposed to H2S-eluting hydrogels. Rat ischemic flap wounds demonstrated greater perfusion at 14 days, and there was greater vascularity of healed wounds compared to untreated animals. A nearly two-fold increase in VEGF mRNA and a four-fold increase in VEGF protein expression were present in wounds from treated animals. Local-regional administration of H2S represents a novel potential therapeutic strategy to promote angiogenesis and improve wound healing after tissue injury or as a result of ischemic disease.

Quantitative Macromolecular Modeling Assay of Biopolymer-Based Hydrogels

The rubber elasticity theory has been lengthily applied to several polymeric hydrogel substances and upgraded from idealistic models to consider imperfections in the polymer network. The theory relies solely on hyperelastic material models in order to provide a description of the elastic polymer network. While this is also applicable to polymer gels, such hydrogels are rather characterized by their water content and visco-elastic mechanical properties. In this work, we applied rubber elasticity constitutive models through hyperelastic parameter identification of hydrogels based on their stress–strain response to compression. We further performed swelling experiments and determined the intrinsic properties, i.e., density, of the specimens and their components. Additionally, we estimated their equilibrium swelling and employed it in the swelling-equilibrium theory in order to determine the polymer–solvent interaction parameter of each hydrogel with regard to cross-linking. Our results show that the average mesh size obtained from the rubber elasticity theory can be regarded as a concentration-dependent characteristic length of the hydrogel’s network and couples the non-linear elastic response to the specimens’ inherent visco-elasticity through hysteresis as a quantifier of energy dissipation under large deformation.

Role of Polymeric Hydrogels in Water Purification: Review

Role of Polymeric Hydrogels in Water Purification: Review