Biopolymer Research Articles

Skin-like dual-network gelatin/chitosan/emodin organohydrogel sensors mediated by Hofmeister effect and Schiff base reaction

Conductive gels have been extensively explored in the field of wearable electronics due to their excellent flexibility and deformability. Traditional gels constructed from synthetic networks pose risks to biosecurity due to residual monomers like acrylamide, while pure biological hydrogels are plagued by inadequate mechanical performance. This study explores an innovative strategy, employing a dual-network (DN) system with purely biological components, as a superior alternative to conventional synthetic networks. By integrating gelatin and chitosan, two natural polymers with inherent biocompatibility and advantageous biomedical properties, this approach successfully avoids the toxic risk of synthetic polymers. By utilizing emodin, a natural extract from Rheum officinale, as a cross-linking agent for chitosan by Schiff base reactions, and Hofmeister effect of gelatin induced by sodium carbonate, the DN gelatin/chitosan/emodin organohydrogels achieve ultrahigh tensile strength (up to 9.45 MPa), tunable moduli (ranging from 0.07 to 3.42 MPa), excellent toughness (~9.64 MJ/m3), and high ionic conductivity (7.63 mS/cm). Remarkably, these conductive organohydrogels also exhibit high sensitivity (gauge factor up to 1.5) and ultrahigh linearity (R2 up to 0.9995), making them promising candidates for soft human-motion sensors capable of accurately detecting and monitoring human movements in real time with high sensitivity and durability.

Polymer Nanocomposites: A Review on Recent Advances in the Field of Green Polymer Nanocomposites

Abstract: In order to address environmental issues, polymer nanocomposites are becoming more and more popular because of their remarkable functionality. Their use in various fields is highlighted by their special physicochemical features (i.e., stability, high reactivity, robustness, regenerability, etc.), conductivity, electronic compatibility, quick interfacial contacts, simplicity of functionalization, simplicity of synthesis, interface-to-volume ratio, and low cost. Green polymer nanocomposites have drawn a lot of attention for use in a variety of applications to preserve the environment. Because they are made of eco-friendly materials, they are frequently utilised in the automobile, building, packaging, and medical industries. Eco-friendly solutions to the problems caused by plastic trash are biodegradable polymers produced from renewable sources (microbes, plants, and animals). Plant fibres and natural resins are combined to create green composite materials. These fibres and resins used in green composites can be broken down by bacteria. The mixing of natural fillers and organic polymers results in green polymer nanocomposites with distinct characteristics. This review is anticipated to be comprehensive, compelling, and practical for the scientists and business professionals who collaborate to address a variety of environmental problems on a global scale using green polymer nanocomposites.

Unveiling the Impact of Absorbent Polymers on Self-healing Efficiency of Sludge-derived Capsules in Cementitious Composites

A novel green capsule for self-healing cementitious material using a combination of waste-based materials with an inorganic substance was developed. A mix of alum sludge (AS), a typical waste from the water industry, and calcium hydroxide were used as the primary healing agents. Also, two types of natural and synthetic absorbent polymers (AP), microcrystalline cellulose (MCC) and sodium polyacrylate (SPA), were added to the core mixture to assess their impact on the healing efficiency. The morphology of the produced capsules, the self-healing proficiency of cracked mortars, and the resulting healing materials were characterised. Outcomes revealed that cracks up to 400µm could be healed by the plain capsule. The closure width was dramatically increased to 500µm and 800µm with the inclusion of MCC and SPA, respectively, mainly in 3 days. The expansion, water retention, and bridging properties of the APs enhanced the sealing performance of the capsules by providing nucleation sites and increasing the reaction rates of core materials to generate further calcium-based products inside the cracks. Therefore, higher recovery rates of mechanical strengths, along with a significant reduction in water ingress were achieved. The main healing products were identified as calcite crystals, C-S-H, calcium silicate, and aluminium-bearing phases.

Conductive Nanocomposites Based on Graphene and Natural Polymers

This thesis focuses on the development of conductive nanocomposite materials based on graphene and natural polymers such as cellulose and chitosan. Graphene, a single layer of carbon atoms arranged in a honeycomb lattice, exhibits exceptional electrical, mechanical, and thermal properties, making it an attractive filler for polymer composites. However, the challenge lies in effectively dispersing graphene sheets within polymer matrices. The work presented explores new strategies for grafting polysaccharide chains onto oxidized graphite (graphene oxide) to improve its compatibility and dispersion in cellulose and chitosan matrices. The resulting composites were doped with gold or nickel nanoparticles to further enhance their electrical and catalytic properties. Detailed characterization techniques, including spectroscopic and microscopic methods, were employed to analyze the structure, morphology, and properties of the developed nanocomposites. The thesis is organized into three main parts: 1) a literature review on graphene, polysaccharides, and their biocomposites; 2) a description of the experimental materials and methods; and 3) a scientific discussion of the results, presented in the form of three research publications. The findings demonstrate the successful synthesis of conductive nanocomposites with improved compatibility and performance, opening up new avenues for the application of these sustainable and multifunctional materials in areas such as electronics, catalysis, and electromagnetic shielding.

Oral mucoadhesive drug delivery system: Formulation strategies and evaluation techniques

Mucoadhesive drug delivery systems (MDDS) represent an innovative method for administering drugs through oral routes such as the buccal, sublingual, and gingival areas. These systems leverage natural or synthetic polymers to ensure prolonged adherence to mucosal surfaces, enabling extended and controlled release of medication. Several factors influence the effectiveness of mucoadhesion, including the hydrophilicity of polymers, molecular weight, and environmental factors like pH and moisture levels. MDDS can take various forms, including tablets, films, patches, lozenges, and gels, each offering different drug release profiles such as immediate, sustained, or controlled. These systems enhance drug bioavailability by avoiding first-pass metabolism, making them particularly beneficial for medications with low oral bioavailability or those requiring targeted delivery. Although MDDS offer improved patient compliance and therapeutic effectiveness, they still face challenges like irritation, taste concerns, and the diluting effect of saliva, which can impact drug stability. Despite these challenges, MDDS hold significant promise for advancing drug delivery technologies across various medical applications. This review thoroughly examines the mechanisms, advantages, limitations, and future prospects of mucoadhesive drug delivery systems.

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.

Adsorption of amoxicillin by chitosan and alginate biopolymers composite beads.

Due to its widespread use and incomplete breakdown in the human body, amoxicillin has been detected in receiving water bodies. This raises significant concerns, like the promotion of antibiotic resistance, toxicity towards aquatic life, disruption of the natural balance of microbial communities within these water bodies, and the struggle of effectively removal by the traditional wastewater treatment plants. Consequently, exploring new processes to complement the existing methods is crucial. Adsorption, a promising highly efficient, selective, and versatile technique, can effectively remove contaminants, making it useful in various industries such as water treatment, pharmaceuticals, and environmental remediation. Several adsorbents are documented in the literature for drug adsorption; however, their fabrication often involves more complex steps and substances compared to chitosan and alginate, which are natural polymers that are biocompatible, non-toxic, and biodegradable. Their tunable properties and ease of modification enhance their efficacy in environmental remediation. Therefore, the novelty of this article is to understand the interaction of amoxicillin with chitosan and alginate adsorbents easily synthetized using the dripping technique. This approach allows us to explore basic principles that can be applied to more complex systems in future studies. The optimal pH for both beads was found to be 4, with adsorption capacities of 74.2 ± 0.3mgg-1 for alginate and 80.4 ± 0.2mgg-1 for chitosan, using 1g of adsorbent. Kinetics studies indicated that external diffusion governs adsorption for alginate, while internal diffusion governs adsorption for chitosan. This approach underscores the potential of chitosan and alginate beads as effective adsorbents for mitigating antibiotic contamination in water systems, offering a sustainable complement to traditional treatment methods.

Alginate-chitosan hydrogel formulations for VEGFA expressed baculovirus delivery promoting angiogenesis for wound healing and revascularization

Abstract Background Baculoviruses, engineered to express growth factors, offer a promising avenue for short-term gene therapy, such as wound dressings, due to their safety and specificity. Encapsulation in natural polymers like alginate and chitosan addresses limitations like serum inactivation and fragility, while promoting sustained delivery and shielding from immune inactivation. Wound healing involves complex processes that can be enhanced by maintaining an antimicrobial, moist environment, which promotes cell migration and angiogenesis. Vascular endothelial cell growth factor A (VEGFA) is known to be one of the most potent pro-angiogenic factors and plays a key role in wound healing. Purpose This investigation seeks to enhance wound healing and angiogenesis, support the revascularization process, and provide anti-inflammatory and anti-microbial effects. Additionally, it aims to assess the preclinical efficacy and safety of the approach. Methods Ionic cross-linking was used for virus encapsulation under aseptic conditions. The capsules were assessed for their surface morphology, particle size, zeta potential, and in vitro release profile. Additionally, their therapeutic potential was studied using cell lines. The efficacy of hydrogel delivery of VEGFA-expressing baculoviruses in promoting cell migration and angiogenesis for wound healing applications was investigated on Human Umbilical Vein Endothelial Cells (HUVECs). Hydrogel morphology, swelling, and encapsulation efficiency were evaluated, along with endothelial tube formation assays and hemocompatibility studies on HUVECs. Results Encapsulation of baculovirus expressing the VEGFA gene in alginate and chitosan–alginate hydrogels achieve a high encapsulation efficiency of 99.9%. This allows for prolonged virus delivery and an increased therapeutic window. The encapsulated baculovirus maintains activity and is released over eight days, with a transduction efficiency of over 40%. This promotes tube formation, cell proliferation, and cell migration for angiogenesis, particularly beneficial for chronic wound-healing applications. The hydrogels also prevented E. coli and C. albicans growth directly below and inhibited C. albicans growth surrounding the alginate–chitosan hydrogels. The hydrogels demonstrated no cytotoxicity and good blood compatibility. Conclusion This proof of concept underscores the potential of encapsulated baculovirus delivery systems for various gene therapy applications including cardiovascular tissue regeneration and revascularization.

Synthesis and characterization of novel electrospun nanofibers based on taro starch: influence of solvent and isolation agent on morphology and diameter

AbstractThe utilization of natural polymers in producing electrospun nanofibers has received significant attention due to their biocompatibility, sustainability and diverse range of applications. This research focuses on synthesizing electrospun nanofibers derived from taro starch isolated from tubers. The investigation utilized SEM to examine the structure and size of the electrospun nanofibers. Formic acid and dimethyl sulfoxide solvents were tested to determine the most efficient solvent system for synthesizing taro starch nanofibers. The results demonstrated that the taro starch nanofibers can be effectively synthesized when using formic acid as the primary solvent. The study also investigated the impact of altering the volumetric ratio of formic acid to water on nanofiber morphology and size, finding that a lower formic acid fraction produced smooth fibers while a higher fraction resulted in fused fibers. The electrospinnability was further evaluated by comparing the effects of different isolation agents—distilled water and sodium metabisulfite—during the isolation process. The isolation agent significantly affected the fiber diameter, with notable differences observed in the smoothness of taro starch nanofibers at starch solution concentrations of 13, 15 and 17 wt%. Overall, the results of the study showed that the formation of taro starch fibers was influenced by the type of solvent, the volume fraction of the solvent to water, and the starch isolation agent. Successful fabrication of nanofibers from taro starch and its optimization parameters can contribute to the development of environmentally friendly nanofiber materials and offer a variety of applications in biomedicine, food and environmental engineering, such as tissue engineering, wound dressing, drug delivery, functional food delivery and food packaging. © 2024 Society of Chemical Industry.

The Influence of the Type and Concentration of Plasticizer on the Properties of Biopolymer Films based on Wild Flax (Camelina Sativa)

The development of biodegradable packaging materials using naturally occurring, renewable biopolymers has gained attraction due to consumer demand for high-quality products and concerns about environmental waste problems. However, the inferior mechanical properties and low water resistance of packaging materials based on natural polymers pose a significant obstacle to their wider use. One of the ways to improve the properties of biopolymer-based packaging materials is the addition of plasticizers during their synthesis. In this work, the influence of the type and concentration of plasticizer on the properties of new biopolymer films based on wild flax (Camelina sativa) was investigated. Camelina sativa oil cake (CSoC) remains after edible oil cold pressing as a by-product. One of the possibilities for its valorization is the synthesis of biopolymer materials. During the synthesis, different plasticizers - glycerol and polyethylene glycol 400 - were added in different concentrations - 20%-60%. The obtained CSoC-based biopolymer films were analyzed for the following properties: Moisture content, solubility, thickness, tensile strength, elongation at break, and water vapor permeability. The results obtained showed significant differences when different plasticizers were applied at different concentrations. The biopolymer film with optimal properties was obtained by adding glycerol at a concentration of 40%.

Programmable and flexible wood-based origami electronics

Natural polymer substrates are gaining attention as substitutes for plastic substrates in electronics, aiming to combine high performance, intricate shape deformation, and environmental sustainability. Herein, natural wood veneer is converted into a transparent wood film (TWF) substrate. The combination of 3D printing and origami technique is established to create programmable wood-based origami electronics, which exhibit superior flexibility with high tensile strength (393 MPa) due to the highly aligned cellulose fibers and the formation of numerous intermolecular hydrogen bonds between them. Moreover, the flexible TWF electronics exhibit editable multiplexed configurations and maintain stable conductivity. This is attributed to the strong adhesion between the cellulose-based ink and TWF substrate by non-covalent bonds. Benefiting from its anisotropic structure, the programmability of TWF electronics is achieved through sequentially folding into predesigned shapes. This design not only promotes environmental sustainability but also introduces its customizable shapes with potential applications in sensors, microfluidics, and wearable electronics.

Evaluation effect of alginate hydrogel containing losartan on wound healing and gene expression.

Skin tissue engineering has become an increasingly popular alternative to conventional treatments for skin injuries. Hydrogels, owing to their advantages have become the ideal option for wound dressing, and they are extensively employed in a mixture of different drugs to accelerate wound healing. Sodium alginate is a readily available natural polymer with advantages such as bio-compatibility and a non-toxicological nature that is commonly used in hydrogel form for medical applications such as wound repair and drug delivery in skin regenerative medicine. Losartan is a medicine called angiotensin receptor blocker (ARB) that can prevent fibrosis by inhibiting AT1R (angiotensin II type 1 receptor). In this research, for the first time, three-dimensional scaffolds based on cross-linked alginate hydrogel with CaCl2 containing different concentrations of losartan for slow drug release and exudate absorption were prepared and characterized as wound dressing. Alginate hydrogel was mixed with 10, 1, 0.1, and 0.01mg/mL of losartan, and their properties such as morphology, chemical structure, water uptake properties, biodegradability, stability assay, rheology, blood compatibility, and cellular response were evaluated. In addition, the therapeutic efficiency of the developed hydrogels was then assessed in an in vitro wound healing model and with a gene expression. The results revealed that the hydrogel produced was very porous (porosity of 47.37 ± 3.76µm) with interconnected pores and biodegradable (weight loss percentage of 60.93 ± 4.51% over 14days). All hydrogel formulations have stability under various conditions. The use of CaCl2 as a cross-linker led to an increase in the viscosity of alginate hydrogels. An in vitro cell growth study revealed that no cytotoxicity was observed at the suggested dosage of the hydrogel. Increases in Losartan dosage, however, caused hemolysis. In vivo study in adult male rats with a full-thickness model showed greater than 80% improvement of the primary wound region after 2weeks of treatment with alginate hydrogel containing 0.1mg/mL Losartan. RT-PCR and immunohistochemistry analysis showed a decrease in expression level of TGF-β1 and VEGF in treatment groups. Histological analysis demonstrated that the alginate hydrogel containing Losartan can be effective in wound repair by decreasing the size of the scar and tissue remodeling, as evidenced by future in vivo studies.

A Review of Advanced Hydrogel Applications for Tissue Engineering and Drug Delivery Systems as Biomaterials

Hydrogels are known for their high water retention capacity and biocompatibility and have become essential materials in tissue engineering and drug delivery systems. This review explores recent advancements in hydrogel technology, focusing on innovative types such as self-healing, tough, smart, and hybrid hydrogels, each engineered to overcome the limitations of conventional hydrogels. Self-healing hydrogels can autonomously repair structural damage, making them well-suited for applications in dynamic biomedical environments. Tough hydrogels are designed with enhanced mechanical properties, enabling their use in load-bearing applications such as cartilage regeneration. Smart hydrogels respond to external stimuli, including changes in pH, temperature, and electromagnetic fields, making them ideal for controlled drug release tailored to specific medical needs. Hybrid hydrogels, made from both natural and synthetic polymers, combine bioactivity and mechanical resilience, which is particularly valuable in engineering complex tissues. Despite these innovations, challenges such as optimizing biocompatibility, adjusting degradation rates, and scaling up production remain. This review provides an in-depth analysis of these emerging hydrogel technologies, highlighting their transformative potential in both tissue engineering and drug delivery while outlining future directions for their development in biomedical applications.

Biodegradation of insecticides: oligonucleotide insecticides and double-stranded RNA biocontrols paving the way for eco-innovation

Each new class of insecticides that emerged during the development of plant protection gradually found the most suitable group of insect pests for application. At the same time, for each individual insecticide, a balance was sought between its effectiveness, on the one hand, and its safety for non-target organisms and the ecosystem as a whole, on the other hand. Neonicotinoids, diamides and pyrethroids, as effective control agents, dominate the insecticide market, but do not have outstanding performance in selectivity and biodegradation. The biodegradation of insecticides is one of the most important indicators, representing what will be said about the hidden costs for the resulting harvest paid by the environment and human health. Oligonucleotide insecticides (contact unmodified antisense DNA (CUAD) biotechnology, or ‘genetic zipper’ method) and RNA biocontrols (double-stranded RNA technology) as natural polymers and the next-generation classes of insecticides possess unique characteristics in fast biodegradation and high selectivity in action. While current chemical insecticides require days, months and even years for biodegradation by bacteria and fungi, oligonucleotide insecticides and RNA biocontrols are substantially biodegraded within hours in the presence of nucleases. Nucleic acid-based insecticides have the potential to complement the existing insecticide market and set an eco-precedent for crop protection products where the effectiveness of the insecticide will be determined by its safety for non-target organisms, and other factors being equal, the choice of a particular control agent will be determined by its biodegradability. It should be noted that not a single class of insecticides that once appeared has completely disappeared; rather, it has occupied its niche, gradually declining under the pressure of new classes of insecticides. At the same time, the common trend in plant protection is towards use of insecticides with higher biodegradability, which gives hope for a safer future of the planet.

Gelatin-Based Polymers Can Be Processed to Highly Resilient Biocompatible Porous Hydrogel Scaffolds for Soft Tissue Regeneration Applications

Tissue regeneration relies on the mechanical properties of the surrounding environment, and it has already been shown that mechanostimulation is highly dependent on the stiffness of the native biological tissue. The main advantage of injectable hydrogels in medical applications is their ability to be delivered through minimally invasive techniques. Natural polymer-based hydrogels have been widely used in biomedical applications, due to their high biocompatibility, low immunogenicity, and similarity to soft tissues. However, the crucial combination of low stiffness with high resilience has not been achieved for natural polymers. The current study focuses on the development of novel gelatin-based injectable hydrogels for soft tissue regeneration applications, elucidating the effects of the formulation parameters on the resilience, microstructure, biocompatibility, and mechanical properties. Non-foamed hydrogels demonstrated resilience of at least 95%, while porous hydrogels maintained resilience above 90%, allowing them to withstand mechanical stresses and dynamic conditions within the body. The adjustable modulus of these hydrogels provides the necessary flexibility to mimic the mechanical properties of soft and very soft tissues, without compromising resilience. Environmental Scanning Electron Microscopy (ESEM) observations of the porous hydrogels indicated round interconnected pore structures, desired for cell migration and nutrient flow. Biocompatibility tests on fibroblasts and pre-adipocytes confirmed high biocompatibility, both directly and indirectly. In summary, structuring these new hydrogels for achieving adjustable stiffness, along with the excellent resilience and biocompatibility, is expected to enable this new technology to fit various soft tissue regeneration applications.

Injectable and pH-Responsive Metformin-Loaded Hydrogel for Active Inhibition of Posterior Capsular Opacification.

Posterior capsular opacification (PCO) is a common complication following cataract surgery, which can lead to a significant vision loss. This study introduces a facile method for developing a metformin-derived hydrogel (HCM6) stabilized by dynamic covalent bonds among natural polymers. This hydrogel demonstrates antifibrotic properties, on-demand drug release, pH responsiveness, injectability, and self-healing capabilities. Our in vitro experiments confirmed that the HCM6 hydrogel exhibits excellent biocompatibility, inhibiting lens epithelial cell migration, and transforming growth factor-2β (TGFβ2)-induced α-smooth muscle actin (α-SMA) expression in lens epithelial cells. In vivo studies conducted in a rat extracapsular lens extraction (ECLE) model revealed that HCM6 significantly suppressed PCO after 21 days of implantation with no observed pathological effects on surrounding tissues or the optic nerve. According to our experimental results, the inhibitory mechanism of PCO may be attributed to metformin's suppressive effect on lens cell migration, epithelial-mesenchymal transition (EMT), and lens fiber formation. In summary, the long-acting, controllable, and on-demand release characteristics of the HCM6 hydrogel not only provide an effective strategy for preventing PCO but also offer new avenues for treating undesirable proliferative conditions in ophthalmology and beyond.

Development of chitosan-acrylic acid based hydrogels with incorporated polyaniline and plasma treatment

Hybrid hydrogels are materials that incorporate features from multicomponent systems of polymers, significantly improving their functionality and making them ideal for biomedical applications. Both natural and synthetic polymers are utilized, further enhancing their functionality. The combination of polyaniline (PANI), chitosan (CS), and acrylic acid (AA) can result in a multifunctional hybrid hydrogel that is antibacterial, hydrophilic, and salt-sensitive. A multifunctional PANI-CS-AA with varying PANI weight ratio was synthesized in this study. In addition, improving the surface of the multifunctional hydrogels by atmospheric pressure plasma (APP) treatment was also investigated. During APP treatment, the production of reactive species (e.g., OH and N2 radicals) responsible for the functionalization of the hydrogel surface was confirmed through optical emission spectroscopy. The integration of three polymer components in the synthesized hydrogels was confirmed through the presence of their mid-FTIR spectral characteristics, particularly in the AA and CS C=O, PANI quinonoid and benzenoid units, AA COO−, and the PANI aromatic and C—H vibration regions. Moreover, the hybrid hydrogels with incorporated PANI and APP treatment improved their wettability and surface free energy (SFE) characteristics. The hybrid hydrogels with 0.25 wt. % PANI and exposed to 2 min air plasma yielded the highest hydrophilicity and total SFE with values 41.27° ± 2.15° and 135.68 ± 4.72 mJ/m2, respectively. The plasma-treated 0.25PANI-2.5CS-4AA samples exhibit improved swelling response in water (Smax = 1310 ± 100; ks = 0.005) and saline media (Smax = 1280 ± 80; ks = 0.001) due to enhanced polymeric chains and affinity toward polar liquids. Synthesized hydrogels exhibited antibacterial activity, as evidenced by the zone of inhibition test. Clearing zones measured were in the range of 16–27 mm. The study developed an APP-treated tricomponent hydrogel consisting of PANI, CS, and AA that has improved hydrophilicity, salt sensitivity, and antibacterial features.

Effect of radiation-induced graft polymerization onto pineapple nonwoven fabric reinforced polymer composite

Natural fiber-reinforced polymer composites are gaining attention for their environmental benefits, such as biodegradability and reduced carbon footprint, as well as the potential of the natural fibers to replace or partially substitute synthetic fibers in various applications. However, challenges, such as poor interfacial adhesion and moisture absorption, limit the effectiveness of natural fibers, such as pineapple nonwoven fabric (PNWF) as reinforcement materials in polymer composites. To address these challenges, this study aims to enhance the properties of PNWF through glycidyl methacrylate grafting via radiation-induced graft polymerization. A 22 factorial design was employed to assess the effects of absorbed dosage and monomer concentration on the properties of the grafted PNWF. Infrared spectroscopy and electron microscopy analyses confirmed successful grafting. The grafted PNWF exhibited improved thermal stability and mechanical properties. The resulting composites showed significant enhancements in tensile and flexural strength, specifically, with tensile strength increase ranging from 23.32 to 34.49 MPa and flexural strength from 39.14 to 54.59 MPa. Additionally, the tensile modulus ranged from 0.77 to 1.29 GPa, while the flexural modulus varied from 1.17 to 2.06 GPa. These findings highlight the potential of PNWF grafted with polyglycidyl methacrylate (PNWF-g-PGMA) as an effective reinforcement material for various applications.

Comparative evaluation of hyaluronic acid-based dressing versus hydrocolloid dressing in rat dermal wound healing

Background: Wound healing is a complex process influenced by a variety of environmental factors. Dressing materials play a critical role in creating barriers against contaminants, maintaining optimal moisture levels, and absorbing wound exudate. Therefore, selecting materials tailored to wound characteristics is crucial for enhancing outcomes. Hyaluronic acid (HA) is a natural biocompatible polymer that supports healing by regulating inflammation and promoting tissue repair. This study compared HA- and hydrocolloid-based hydrogels in a rat model to optimize wound care strategies.Methods: Full-thickness dermal wounds (diameter, 8 mm) were created on the dorsal skin of 12 Sprague-Dawley rats under sevoflurane anesthesia. The wounds were treated with HA/silver sulfadiazine gel (group A), hydrocolloid gel (group B), or left untreated (control), all covered with a transparent dressing. Biopsy specimens on days 3, 7, and 21 were used to assess histological parameters: inflammatory cell infiltration, fibroblast infiltration, collagen deposition, neovascularization, and epithelial thickness, using a semi-quantitative scoring system. Histological analyses were conducted blindly, and statistical analyses were performed using the Kruskal-Wallis test (<i>p</i>< 0.05).Results: On day 3, group A showed significantly higher inflammatory cell infiltration and collagen deposition than other groups, indicating extracellular matrix formation. By day 7, angiogenesis was highest in group A, followed by group B and controls. By day 21, all wounds had completely healed. Epithelial layer thickness, reflecting inflammation and fibroblast maturity, was significantly higher in group A.Conclusion: This study compared HA-based hydrogel and hydrocolloid-based dressings through histological analyses to elucidate wound healing mechanics. HA-based hydrogel dressings significantly enhanced wound recovery. However, generalizing these outcomes requires future studies to expand the range of effective wound treatment materials. These findings underscore the potential of HA-based dressings to enhance clinical outcomes in wound management, suggesting avenues for improving therapeutic strategies.

3D Coaxial Printing of Small‐Diameter Artificial Arteries

As a treatment for the widely spread cardiovascular diseases (CVD), bypass vascular grafts have room for improvement in terms of mechanical property match with native arteries. A 3D‐printed nozzle is presented, featuring unique internal structures, to extrude artificial vascular grafts with a flower‐mimicking geometry. The multilayer‐structured graft wall allows the inner and outer layers to interfere sequentially during lateral expansion, replicating the nonlinear elasticity of native vessels. Both experiment and simulation results verify the necessity and benefit of the flower‐mimicking structure in obtaining the self‐toughening behavior. The gelation study of natural polymers and the utilization of sacrificial phase enables the smooth extrusion of the multiphase conduit, where computer‐assisted image analysis is employed to quantify manufacturing fidelity. The cell viability tests demonstrate the cytocompatibility of the gelatin methacryloyl (GelMA)/sodium alginate grafts, suggesting potential for further clinical research with further developments. This study presents a feasible approach for fabricating bypass vascular grafts and inspires future treatments for CVD.