Chemical Cross-linking Agents Research Articles

In vitro chronic wound healing using collagen and plant extract along with zinc nanoparticles

INTRODUCTION: While the use of zinc nanoparticles (ZnNPs) as an antibacterial agent in the biomedical industry has recently attracted significant attention, collagen has aroused significant interest as a biomaterial in medical and tissue engineering applications.
 OBJECTIVES: In order to create biofilm loaded with biosynthesized ZnNPs for use in chronic wound healing applications, type-I collagen was extracted from the study's subject. by the acid soluble collagen technique, collagen was isolated from the fish skin of the trevally and identified by SDS-PAGE. Aqueous extract from Cassia fistula leaves was also used to greenly manufacture stable ZnNPs, which were then characterized by UV-Vis, FTIR, and XRD measurements.
 METHODS: Collagen and ZnNPs were then added to polyvinyl alcohol (PVA), creating a thin biofilm that had a high biocompatibility due to the production method's absence of a chemical reducer and crosslinking agent. When tested against the harmful bacteria, both ZnNPs alone and PVA/Collagen/ZnNPs biofilms showed potent antibacterial activity.
 RESULTS: By using the MTT test, the cytotoxic effects of collagen and ZnNPs on the Vero cell line were evaluated. With 97.76% wound closure, the PVA/Collagen/ZnNPs biofilm demonstrated strong in vitro wound scratch healing efficacy.
 CONCLUSION: The findings show that the PVA/Collagen/ZnNPs film dramatically increased cell migration by 40.0% at 24 hours, 79.20% at 48 hours, and 97.76% at 74 hours.

Emulsion synthesis of cellulose/lanthanum alginate /La (Ⅲ) composite microspheres for efficient and selective adsorption of phosphate

Phosphorus exceeding the standard will destroy the ecological environment of the freshwater resources and endanger the survival of aquatic animals. Due to the intrinsic complexation between La(Ⅲ) and alginate, in this study, lanthanum hydroxide was first prepared from lanthanum nitrate, the chemical crosslinking agent was replaced by La(Ⅲ), and cellulose/lanthanum alginate/La(OH)3 composite microspheres (CSPGs-La) were synthesized using polyethyleneimine (PEI) as a crosslinking agent through the emulsification process in one pot. In comparison, the adsorption capacity of 80 mg L−1 PO43− treated with CSPGs-La, CSPGs-Ech (Samples where the chemical crosslinking agent was not replaced by La(Ⅲ)) and La(OH)3 was 159.5 mg g−1, 57.51 mg g−1 and 137.4 mg g−1, respectively. CSPGs-La has good swelling performance, unique three-dimensional structure and mass transfer efficiency, which are the important reasons for its strong ability to capture phosphate. In the presence of coexisting anions, CSPGs-La can still accurately adsorb PO43−, showing good adsorption selectivity. Intra-surface spherical complexation and electrostatic adsorption play an important role. When the dose of CSPGs-La is 1.35 g L−1, the phosphorus pollutants in the actual domestic sewage can be reduced to 10 μg L−1 below. After five adsorption cycles, the retention rate of phosphorus removal performance is 87.7 %. This study provides a green, easy to implement, and promising solution for the preparation of efficient and selective phosphorus removal adsorbent.

Recoverable and degradable carboxymethyl chitosan polyelectrolyte hydrogel film for ultra stable encapsulation of curcumin

Hydrogels have shown great potential for application in food science due to their diverse functionalities. However, most hydrogels inevitably contain toxic chemical cross-linking agent residues, posing serious food safety concerns. In this paper, a curcumin/sodium alginate/carboxymethyl chitosan hydrogels (CSCH) were prepared by self-assembly of two oppositely charged polysaccharides, carboxymethyl chitosan and sodium alginate, to form a three-dimensional network encapsulating curcumin for extending food shelf life. The network structure of the CSCH film confirmed by FTIR, XRD, and XPS was mainly formed by electrostatic interactions. The chemical stability of CSCH network encapsulated curcumin was 4.2 times greater than that of free curcumin, with excellent gas barrier, antimicrobial, antioxidant, and biosafety properties. It was found that CSCH films reduced dehydration, prevented nutrient loss, inhibited microbial growth, and lowered the respiration rate, which effectively maintained the quality of mango and prolonged its shelf-life up to 11 days. Notably, CSCH films possessed the properties of rapid recycling (10 mins) and biodegradability (53 days). This polysaccharide-based hydrogel film provides a viable strategy for the development of green and sustainable food packaging.

A microscale 3D organ on a chip for recapitulating reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland

Conventional 2D or even recently developed 3D in vitro culture models for hypothalamus and pituitary gland cannot successfully recapitulate reciprocal neuroendocrine communications between these two pivotal neuroendocrine tissues known to play an essential role in controlling the body’s endocrine system, survival, and reproduction. In addition, most current vitro culture models for neuroendocrine tissues fail to properly reflect their complex multicellular structure. In this context, we developed a novel microscale chip platform, termed the ‘hypothalamic–pituitary (HP) axis-on-a-chip,’ which integrates various cellular components of the hypothalamus and pituitary gland with biomaterials such as collagen and hyaluronic acid. We used non-toxic blood coagulation factors (fibrinogen and thrombin) as natural cross-linking agents to increase the mechanical strength of biomaterials without showing residual toxicity to overcome drawbacks of conventional chemical cross-linking agents. Furthermore, we identified and verified SERPINB2 as a reliable neuroendocrine toxic marker, with its expression significantly increased in both hypothalamus and pituitary gland cells following exposure to various types of toxins. Next, we introduced SERPINB2-fluorescence reporter system into loaded hypothalamic cells and pituitary gland cells within each chamber of the HP axis on a chip, respectively. By incorporating this SERPINB2 detection system into the loaded hypothalamic and pituitary gland cells within our chip platform, Our HP axis-on-chip platform can better mimic reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland in the brain microenvironments with improved efficiency in evaluating neuroendocrine toxicities of certain drug candidates.

Anti-freezing, tough, and stretchable ionic conductive hydrogel with multi-crosslinked double-network for a flexible strain sensor

Ionic conductive hydrogels are an ideal material for use in flexible strain sensors due to their electrical conductivity, accurate data retrieval, and extensibility. However, conventional ionic conductive hydrogels including salt/organics or salt-based hydrogels with high ionic content exhibit modest antifreeze and limited mechanical properties, hampering their practical use across diverse sectors. The preparation process is tedious due to the incorporation of toxic photoinitiator and chemical crosslinking agents. Herein, through a simple, low-cost, and environmentally friendly strategy, we have developed a multi-crosslinked double network ionic conductive hydrogel by using polyvinyl alcohol bearing styrylpyridinium groups (PVA-SbQ) and sodium alginate (SA) via UV irradiation, followed by immersion in a mixed solution of ferric chloride (FeCl3) and glycerol (Gly)/water. This synergistic effect of FeCl3 and Gly has endowed the PVA-SbQ/SA/FeCl3/Gly hydrogel with exceptional mechanical properties (tensile strength of 2.48 ± 0.45 MPa and elongation at break of 1452 ± 101 %), anti-freezing ability (-42.3 °C), and electrical conductivity of 0.38 S/m and 0.32 S/m at room temperature and −30 °C, respectively. Moreover, the hydrogel exhibits remarkable strain sensitivity (GF = 2.49), allowing it to be used as a strain sensor under both room temperature and subzero conditions. Consequently, the prepared hydrogel sensor can monitor various human motions, such as joint bending, running, and speaking. Therefore, our work offers a promising strategy for the preparation of PVA-based hydrogels with outstanding mechanical properties, electrical conductivity, and resistance to freezing, rendering them a practical option for flexible sensors. In addition, our anti-freezing method has significant potential in enhancing the accessibility of ionic conductive hydrogels.

Preparation and Application of Polyrotaxane Cross-Linking Agent Based on Cyclodextrin in Gel Materials Field.

The cross-linking point of a conventional chemical cross-linking agent is fixed. Therefore, gels that are prepared with a conventional cross-linking agent have poor deformability, strength, shear resistance, and further properties. Some researchers have prepared a new cross-linking agent using cyclodextrin (CD). In a polyrotaxane cross-linking agent, the cross-linking points can slide freely along the molecule chain. The special "slide ring" structure can provide better elongation, strength, and other properties to gels, which can effectively expand the application of the gel's materials. This paper summarizes the preparation methods and applications from different types of CD and compares the improvements of properties (swelling, viscoelastic properties, etc.). In addition, the current results of our group are presented, and some ideas are provided for the development of polyrotaxane cross-linking agents.

Degradable carrier-free spray hydrogel based on self-assembly of natural small molecule for prevention of postoperative adhesion.

Postoperative peritoneal adhesion (PPA) is frequent and extremely dangerous complication after surgery. Different tactics have been developed to reduce it. However, creating a postoperative adhesion method that is multifunctional, biodegradable, biocompatible, low-toxic but highly effective, and therapeutically applicable is still a challenge. Herein, we have prepared a degradable spray glycyrrhetinic acid hydrogel (GAG) based on natural glycyrrhetinic acid (GA) by straightforward heating and cooling without the use of any additional chemical cross-linking agents to prevent postoperative adhesion. The resultant hydrogel was demonstrated to possess various superior anti-inflammatory activity, and multiple functions, such as excellent degradability and biocompatibility. Specifically, spraying characteristic and excellent antibacterial activities essentially eliminated secondary infections during the administration of drugs in surgical wounds. In the rat models, the carrier-free spray GAG could not only slow-release GA to inhibit inflammatory response, but also serve as physical anti-adhesion barrier to reduce collagen deposition and fibrosis. The sprayed GAG would shed a new light on the prevention of postoperative adhesion and broaden the application of the hydrogels based on natural products in biomedical fields.

Enhanced sensing performance of EVA/LDPE/MWCNT piezoresistive foam sensor for long-term pressure monitoring

Conductive polymer composites (CPCs) with piezoresistive properties are smart detecting systems with high sensitivity, fast response, and low energy consumption. To enhance their sensitivity and cope with their high filler content requirements, solid CPCs are normally transformed into blends and foams, which reduces the elastic modulus, enabling larger deformations, wider detection range, and increased sensitivity. However, providing reversible and durable sensing properties remains challenging as it depends on the phase morphology, foam cell structure, and particle dispersion. To this end, we use multi-walled carbon nanotube (MWCNT) as a conductive filler with a high aspect ratio and develop CNT-filled ethylene vinyl acetate/low-density polyethylene (EVA/LDPE) blend foams. We fix the foam structure using chemical foaming and crosslinking agents in a compression molding process. To optimize the piezoresistive behavior, we follow a step-wise tuning approach, studying the blending morphology, the foaming attributes, the particle dispersion and affinity, thereby selecting the most promising formulations for further investigations. The least mechanical and electrical hysteresis is obtained at minimum foam density, which is obtained at a compromised crystallinity and crosslinking density. The higher affinity of MWCNT to EVA and the faster crosslinking of the EVA phase results in uniformly dispersed small cells at EVA-rich formulations and 4 phr MWCNT content. The final foam sensor demonstrates an impressive response and recovery times of less than 200 ms and remarkable durability thanks to the optimized cell morphology and mechanical properties. These findings expand the application of carbon-filled polyolefin foams in pressure monitoring, particularly in wearable sensors for strain and motion sensing.

Effects of TiO2 nanoparticles on the physicochemical and biological properties of oxidized sodium alginate/polyacrylamide-gelatin composite hydrogels fabricated by interpenetrating network approach

To enhance the applicability of alginate hydrogel in tissue engineering, we attempted to fabricate oxidized sodium alginate/polyacrylamide-gelatin (OSA/PAM-GT) composite hydrogels by interpenetrating network approach with the hydroxyapatite/D-glucono-δ-lactone (HAP/GDL) as the endogenous ionic cross-linking agent for oxidized sodium alginate (OSA) and N, N′-methylenebisacrylamide (MBAA) as the chemical cross-linking agent for polyacrylamide (PAM), followed by their surface coverage with gelatin. Then TiO2 nanoparticles as the reinforcing agent were added to the OSA/PAM-GT hydrogel matrix to construct organic/inorganic hybrid OSA/TiO2/PAM-GT composite hydrogels. In particular, the effects of the amount of TiO2 nanoparticles on the microscopic morphology, mechanical properties, swellability, biodegradability, bio-mineralization and biocompatibility of the composite hydrogels were studied. Experimental results indicated that the addition of TiO2 nanoparticles into the matrix of OSA/TiO2/PAM-GT composite hydrogels could effectively regulate the porosity, mechanical properties, swelling ratio, in vitro biodegradability and bio-mineralization of OSA/TiO2/PAM-GT composite. Moreover, OSA/TiO2/PAM-GT composite hydrogels had the best biocompatibility when the content of TiO2 nanoparticles was 0.5% (w/v), indicating that an appropriate amount of TiO2 nanoparticles could effectively promote cell adhesion, proliferation and differentiation. Consequently, the combined method of the interpenetrating network technology, the incorporation of TiO2 nanoparticles with the surface coverage of gelatin could overcome the defects of alginate hydrogels to some extent, making OSA/TiO2/PAM-GT composite hydrogels suitable for tissue engineering applications.

Pea Protein-Based Bioplastics Crosslinked with Genipin: Analysis of the Crosslinking Evolution

Replacing conventional plastics with other products obtained from biobased and biodegradable raw materials is an increasingly studied solution. In this line, the development of protein-based bioplastics is a promising alternative. However, for some applications, such as packaging it would be necessary to improve their properties by including an additional stage to crosslink the protein chains during the production of bioplastics. Therefore, pea protein-based bioplastics crosslinked with genipin, a natural non-toxic chemical crosslinking agent, are evaluated in this study. The bioplastics are obtained via injection moulding and genipin, is included in the initial formulation. Specifically, the concentration of genipin and the effects on the protein blends with genipin over days are evaluated. The evolution of the reaction is followed by the colour change of the blend, together with thermal analyses and infrared spectroscopy. Results showed the evolution of the crosslinking in the blends resulted in conformational changes that resulted in the modification of the initial yellowish colour to a blueish system. Respect their bioplastics, more deformable systems with a lower water absorption capability are obtained by using genipin as crosslinking agent.

Preparation and characterization of a biocompatible glucose-sensitive electrospun nanofibers scaffolds containing dexamethasone with enhanced osteogenic properties in vitro high glucose environment

Diabetes has made it challenging to repair alveolar bone defects. A successful method for bone repair utilizes a glucose-sensitive osteogenic drug delivery. This study created a new glucose-sensitive nanofiber scaffold with controlled dexamethasone (DEX) release. DEX-loaded polycaprolactone/chitosan nanofibers scaffolds were created using electrospinning. The nanofibers had high porosity (>90%) and proper drug loading efficiency (85.51 ± 1.21%). Then, glucose oxidase (GOD) was immobilized on the obtained scaffolds by a natural biological cross-linking agent, genipin (GnP), after soaking in the mixture solution containing GOD and GnP. The enzyme properties and glucose sensitivity of the nanofibers were investigated. The results showed that GOD was immobilized on the nanofibers and exhibited good enzyme activity and stability. Meanwhile, the nanofibers expanded gradually in response to the increase in glucose concentration, followed by the release of DEX increased. The phenomena indicated that the nanofibers could sense glucose fluctuation and possess favorable glucose sensitivity. In addition, the GnP nanofibers group showed lower cytotoxicity in the biocompatibility test compared with a traditional chemical cross-linking agent. Lastly, the associated osteogenesis evaluation found that the scaffolds effectively promoted MC3T3-E1 cells’ osteogenic differentiation in high-glucose environments. As a result, the glucose-sensitive nanofibers scaffolds offer a viable treatment option for people with diabetes with alveolar bone defects.

L’organisation native de la cellule révélée grâce à la cryo-microscopie à expansion

Most cellular imaging techniques, such as light or electron microscopy, require that the biological sample is first fixed by chemical cross-linking agents. This necessary step is also known to damage molecular nanostructures or even sub-cellular organization. To overcome this problem, another fixation approach was invented more than 40 years ago, which consists in cryo-fixing biological samples, thus allowing to preserve their native state. However, this method has been scarcely used in light microscopy due to the complexity of its implementation. In this review, we present a recently developed super-resolution method called expansion microscopy, which, when coupled with cryo-fixation, allows to visualize at a nanometric resolution the cell architecture as close as possible to its native state.

Preparation and Properties of Carboxymethyl Cellulose / β-Cyclodextrin Hydrogel

Carboxymethyl cellulose (CMC) based hydrogels provide superabsorbent properties but show low mechanical properties. In order to overcome this problem, β-cyclodextrin (CD) is added to improve the mechanical strength of hydrogels. Moreover, CD-containing hydrogels have the potential to encapsulate antimicrobial essential oils or drugs and give a sustained release for medical applications to treat a variety of bacterial infectious diseases causing destruction to human health. In this work, the CMC/CD hydrogels were prepared by using epichlorohydrin as a chemical crosslinking agent. The objective of this research was to study the effect of the CMC/CD weight ratio at 6:1, 7:1, and 8:1 on morphology, mechanical properties and swelling ratio in water of the CMC/CD hydrogels compared with CMC hydrogel. The weight ratio of epichlorohydrin and CMC/CD was constant at 6:1. The morphology analysis of the CMC/CD hydrogels showed an irregular porous structure with the presence of -like structure. The addition of CD content led to an increase in compressive strength whereas the swelling ratio of the hydrogel decreased. The CMC/CD hydrogel at weight ratio of 7:1 provided the highest compressive strength and also retained swelling ability.

Improvement of Heat Resistance of Fluorosilicone Rubber Employing Vinyl-Functionalized POSS as a Chemical Crosslinking Agent.

Fluorosilicone rubber (F-LSR) is a promising material that can be applied in various cutting-edge industries. However, the slightly lower thermal resistance of F-LSR compared with that of conventional PDMS is difficult to overcome by applying nonreactive conventional fillers that readily agglomerate owing to their incompatible structure. Polyhedral oligomeric silsesquioxane with vinyl groups (POSS-V) is a suitable material that may satisfy this requirement. Herein, F-LSR-POSS was prepared using POSS-V as a chemical crosslinking agent chemically bonded with F-LSR through hydrosilylation. All F-LSR-POSSs were successfully prepared and most of the POSS-Vs were uniformly dispersed in the F-LSR-POSSs, as confirmed by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements. The mechanical strength and crosslinking density of the F-LSR-POSSs were determined using a universal testing machine (UTM) and dynamic mechanical analysis (DMA), respectively. Finally, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements confirmed that the low-temperature thermal properties were maintained, and the heat resistance was significantly improved compared with conventional F-LSR. Eventually, the poor heat resistance of the F-LSR was overcome with three-dimensional high-density crosslinking by introducing POSS-V as a chemical crosslinking agent, thereby expanding the potential fluorosilicone applications.

Fabrication of photochromic and electrochromic (PVP-am)/WO3/MoO3 hydrogel composites and glass films with programmable shapes

Recently, the fabrication of functional and stimuli-responsive hydrogels using deep eutectic solvent derivatives is gaining tremendous scientific recognition owing to their unique self-switching properties. In this study, perfluorinated deep eutectic mixtures were prepared as the template for the synthesis of WO3/MoO3 composites. The metal oxide-based composites were further employed as a chemical crosslinking agent for the polymerization of polyvinyl pyrrolidine (PVP) and acrylamide (Am), for the construction of (PVP-Am)/WO3/MoO3 hydrogel composites. The hydrogels displayed unique morphologies and mechanical properties. The hydrophilic nature of hydrogels as well as the high concentration of dispersed WO3/MoO3 composites in the polymer network contributes to their photochromic activity and allows an immediate coloration upon exposure to light at a short time. Howbeit, the low concentration of the dispersed WO3/MoO3 composites in the dry glass membrane is responsible for the blue coloration and an extended time of photochromic response. In addition, the electrochromic behavior of the hydrogel composites displayed a strong quasi-rectangular shape potential window as well as a well-defined redox cyclic voltammetry curve when exposed to high voltage. This could be due to the photoredox property of the WO3/MoO3 composites responsible for charge transfer between the different oxidation states.

3D printing surimi enhanced by surface crosslinking based on dry-spraying transglutaminase, and its application in dysphagia diets

Dry-spraying transglutaminase (TG) was explored as surface modification agent for enhancing the surimi structures and promoting its practical 3D printing application. Glycerol functionalization, 3D extruding critical parameters, TG based surface crosslinking, practical cooking loss, and innovative applications of 3D-printed surimi were investigated. Rheological performances (shear ramp, strain sweep and thixotropy tests) indicate that glycerol could enhance excellent pseudo plasticity (fluid behavior index n < 1), high mechanical strength & strain resistance (high G′, and wide linear viscoelastic region 2.51%), and outstanding thixotropy (high recovery rates, up to 61.47%) of surimi, owing to that glycerol could promote the hydration of surimi myosin and prevent protein aggregation by stabilizing aggregation-prone intermediates. The further optimization of the extruding parameters (nozzle diameter 1.00 mm and “Rectilinear” filling structure) would improve the surimi dimensional printing deviations, and increase surimi gel strength (up to 22.29 g mm) by regulating interlayer bonding zones. Compared with chemical crosslinking agents NaCl and CaCl2 for modifying surimi, surface crosslinking based on dry-spraying TG would better raise the printable height efficiency (97.50%), improve the surimi texture, and enhance suitable water distribution, resulting in fine and dense network by hydrophobic interactions, disulfide bonds and non-disulfide covalent bonds. Subsequently, the cooking loss tests and International Dysphagia Diet Standardization Initiative tests proved that 3D-printed surimi could be classified as a potential transitional food for dysphagia groups. Surface crosslinking based on dry-spraying TG suggests a bright promise in practical high-accuracy, sophisticated 3D printing of surimi and holds potential in dysphagia diets and innovating food products.

Supramolecular self-assembling hydrogel film based on a polymer blend of chitosan/partially hydrolyzed polyacrylamide for removing cationic dye from water

The supramolecular self-assembling hydrogel film was designed using a polymer blend of chitosan and partially hydrolyzed polyacrylamide (CS/PHPA), which was constructed with a controllable sol-gel transition, using a green one-pot external salt-assisted sol-gel transition and aqueous solution casting method that does not employ any toxic chemical crosslinking agents. The structure of hydrogel film was confirmed by zeta potential, FT-IR, XRD, SEM, EDX, and TG/DTGA. The swelling properties of gels were well investigated and the results revealed a rapid swelling rate. Notably, the composite hydrogel film exhibited remarkable thermo- and pH-induced sol-gel transitions. The zeta potential of supramolecular CS/PHPA hydrogel was −51.5 mV (pH 7.0), which provided a good adsorption performance for the cationic dye methyl blue (MB). The adsorption process obeyed the pseudo-second-order kinetic model and the maximum adsorbed amount for MB was high up to 282 mg/g. The adsorption equilibrium data correlated well with the Langmuir model, suggesting that the MB was removed through the monolayer and physical adsorption mechanism. After five adsorption/desorption cycles using a mixture of (HCl:1-Butanol) as eluent, the dye adsorption efficiency decreased from 96.45 to 79.80%. The possible adsorption mechanism is believed to be the non-covalent interactions (the electrostatic interactions together with hydrogen bonding between the N atom of MB and the H atom of functional groups of the hydrogel. Overall, the “green” gelation process provides a new opportunity for the rational design of self-assembling physical hydrogels as adsorbents for cationic and anionic dye removal.

Antifouling thin-film nanocomposite NF membrane with polyvinyl alcohol-sodium alginate-graphene oxide nanocomposite hydrogel coated layer for As(III) removal

Removal of As(III) from the polluted waters is a challenge. It should be oxidized to As(V) for increasing its rejection by RO membranes. However, in this research, As (III) is directly removed by a high permeable and antifouling membrane prepared through the surface coating and in-situ crosslinking procedure of polyvinyl alcohol (PVA) and sodium alginate (SA) as coating materials containing graphene oxide as a hydrophilic additive on a polysulfone support with glutaraldehyde (GA) chemical crosslinking agent. The properties of the prepared membranes were evaluated through contact angle, zeta potential, ATR-FTIR, SEM, and AFM. The addition of GO in the polymeric networks of SA and PVA hydrogel coating layers led to a better hydrophilicity and a smoother surface and a higher negative surface charge resulted in improvment of permeability and rejection of membranes. Among the prepared hydrogel-coated modified membranes, SA-GO/PSf indicated the highest pure water permeability (15.8 L m−2 h−1 bar−1) and BSA permeability (9.57 L m−2 h−1 bar−1), respectively. The best desalination performance (NaCl, MgSO4, and Na2SO4 rejections of 60.0%, 74.5%, and 92.0%, respectively) and As(III) removal (88.4%) along with satisfactory stability and reusability in cyclic continuous filtration was reported for PVA-SA-GO membrane. In addition, the PVA-SA-GO membrane indicated improved fouling resistance toward BSA foulant with the lowest flux decline of 7%.

Bioengineered Water-Responsive Carboxymethyl Cellulose/Poly(vinyl alcohol) Hydrogel Hybrids for Wound Dressing and Skin Tissue Engineering Applications.

The burden of chronic wounds is growing due to the increasing incidence of trauma, aging, and diabetes, resulting in therapeutic problems and increased medical costs. Thus, this study reports the synthesis and comprehensive characterization of water-responsive hybrid hydrogels based on carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) using citric acid (CA) as the chemical crosslinking agent, with tunable physicochemical properties suitable to be applied as a wound dressing for soft tissue engineering applications. They were produced through an eco-friendly process under mild conditions. The hydrogels were designed and produced with flexible swelling degree properties through the selection of CMC molecular mass (Mw = 250 and 700 kDa) and degree of functionalization (DS = 0.81), degree of hydrolysis of PVA (DH > 99%, Mw = 84-150 kDa) associated with synthesis parameters, CMC/PVA ratio and extension of chemical crosslinking (CA/CMC:PVA ratio), for building engineered hybrid networks. The results demonstrated that highly absorbent hydrogels were produced with swelling degrees ranging from 100% to 5000%, and gel fraction from 40% to 80%, which significantly depended on the concentration of CA crosslinker and the presence of PVA as the CMC-based network modifier. The characterizations indicated that the crosslinking mechanism was mostly associated with the chemical reaction of CA carboxylic groups with hydroxyl groups of CMC and PVA polymers forming ester bonds, rendering a hybrid polymeric network. These hybrid hydrogels also presented hydrophilicity, permeability, and structural features dependent on the degree of crosslinking and composition. The hydrogels were cytocompatible with in vitro cell viability responses of over 90% towards model cell lines. Hence, it is envisioned that this research provides a simple strategy for producing biocompatible hydrogels with tailored properties as wound dressings for assisting chronic wound healing and skin tissue engineering applications.

Nanocellulose aerogels from banana pseudo-stem as a wound dressing

Wound dressings with natural antimicrobial, moisturizing and swelling properties have received increasing attention. However, many natural materials used as wound dressings require chemical cross-linking agents or acidic and alkaline environments and have problems such as poor stability and uneven distribution. In this study, banana nanocellulose (BCNF) with a diameter of less than 70 nm was extracted from banana pseudo-stem through benzyl alcohol extraction, sodium chlorite bleaching, potassium hydroxide alkaline treating, and ultrasonic crushing treatment. There was an addition of konjac glucomannan (KGM) to 0.8 wt% nanocellulose suspension and freeze-drying to form composite aerogel (BCNK) by freeze-drying. Different ratios of BCNF and KGM were used to regulate the performance of aerogels such as swelling, water retention, water vapor transmission rate, and mechanical property. It was evident that the aerogel with an 8/2 mass ratio of BCNF to KGM (BCNK2) exhibited better performance, with a 2981% swelling rate, 97.71% porosity, and 810 g·m−2·d−1 water vapor transmission rate, and also showed the applicable mechanical properties. According to the results of antibacterial and biocompatibility, the composite aerogel had commendable inhibitory effects on E. coli and S. aureus. The hemolysis rate of BCNK2 was 3.38% and the cell survival rate was over 90%, which proved that BCNK2 had good hemolysis and no cytotoxicity. Therefore, the nanocellulose composite aerogel prepared from banana pseudo-stem has the potential to be applied to wound dressings.