PVA/CMC/Attapulgite Clay Composite Hydrogel Membranes for Biomedical Applications: Factors Affecting Hydrogel Membranes Crosslinking and Bio-evaluation Tests

Abstract

Herein, polyvinyl alcohol-carboxymethyl cellulose (PVA-CMC) composite hydrogel membranes were prepared using solution-casting method, where citric acid (CA) was added as crosslinker in different ratios of (7, 10 and12 wt%). Attapulgite clay extracted from Northwestern Desert of Borg El-Arab, Egypt; was incorporated as nanofiller (1, 2, 4, and 5 wt%) into membranes for improving their mechanical/ thermal stability. Results revealed that, physicochemical properties of membranes e.g. swelling%, tensile strength and morphology of membranes affected significantly by different clay concentrations and citric acid crosslinker. Also, attapulgite clay with concentration 1 (wt%) enhanced mechanical strength of composite membranes, compared to other clay concentrations. Furthermore, protein adsorption %, hydrolytic degradation, hemolysis (%) and antimicrobial activity significantly affected by clay contents and CA concentrations. Four bacterial pathogens e.g. Candida albicans, Escherichia coli, Klebsiella pneumoniae, and Bacillus cereus were used for testing antimicrobial activity of prepared membranes. Results referred to increasing of clay contents led to a high hemolysis %; however, increasing CA concentration significantly reduced hemolysis %. Meanwhile, membranes with low clay contents offered the most effective resistance against tested microbes. These findings are referring to the ability of using PVA-CMC-attapulgite composite membranes crosslinked by CA as good candidate of biomaterials for dermal wound dressings.

Novel Physically Cross-Linked Curcumin-Loaded PVA/Aloe vera Hydrogel Membranes for Acceleration of Topical Wound Healing: In Vitro and In Vivo Experiments

“…Figure 2b shows XRD patterns of native PVA, cross-linked PVA and PVA/Aloe vera cross-linked hydrogel membranes, [48]. This result is completely consistent with the hypothesis that noncross-linked PVA was a partly crystalline substance which shows two peaks at 2º ~19.7°and 40.57°where the latter pattern sometimes overlaps with other patterns [42,43]. While cross-linked PVA is a more crystalline than non-crosslinked which is presenting more peak area, the overlapped four patterns are detected at 2º ~19.7, 20.39, 23.6°and 41.24°.…”

“…S1, Supplementary materials) and Scheme 1. The proposed reaction mechanism that explains the fully hydrolyzing of PVA by addition of alcohol has been previously stated [41,42].…”

Production of Polymer Hydrogel Composites and Their Applications

“…By combining chemical crosslinkers with polymers and creating covalent bonds, chemically crosslinked hydrogels are created. Since it does not dissolve in water without rupturing covalent bonds, this type of hydrogel is stable and long-lasting [43]. A completely cross-linked hydrogel has less design flexibility since it is challenging to decouple elements like gelation time, inward network pore size, functionalization, and degradation time.…”

“…Before or after the polymerization, groups like carboxylic acid in the product are partly neutralized. In this process, the initiation is often accomplished chemically with a free-radical azo or peroxide thermal dissociative species or by the interaction of a reducing agent with an oxidizing agent (redox system) [43]. However, this approach is preferable at both laboratory and industrial scales because of its quick process, lower cost, and acceptable swelling qualities.…”

Preparation of Food Grade Superhydrophobic Coatings Based on Attapulgite Nanorods

“…Furthermore, APT is a water-rich magnesium aluminum silicate crystalline clay mineral with nanorod-like morphology. APT has received extensive attention in various fields, such as agriculture, environmental protection, cosmetics, textile printing and dyeing, food, and medicine . We have successfully prepared some superhydrophobic or superamphiphobic coatings with a good performance by constructing micro-/nanostructures using APT instead of synthetic nanomaterials. − However, these coatings aim at applications in oil/water separation, anti-icing, and anticorrosion and are not applicable to the food industry.…”