Structure–Property–Antimicrobial Relationships of Citric Acid-Crosslinked PVA–Starch Scaffolds Loaded with Gambier Polyphenols

The development of bioactive polymeric scaffolds for wound dressing requires a balanced integration of structural stability, controlled fluid uptake behavior, and antimicrobial functionality. In this study, citric acid-crosslinked polyvinyl alcohol (PVA)–Belitung taro starch composite scaffolds incorporating gambier (Uncaria gambir) extract were fabricated via solution casting, and the interrelationship between structural characteristics, mechanical properties, swelling behavior, and antimicrobial performance was systematically evaluated. Fourier transform infrared (FTIR) analysis confirmed the formation of hydrogen bonding interactions among PVA, starch, and phenolic compounds from gambier extract, along with ester linkages induced by citric acid crosslinking, suggesting the formation of a semi-interpenetrating polymer network-like structure. Mechanical testing revealed that increasing PVA concentration significantly influenced elastic modulus, tensile strength, and elongation behavior, with the TSVA-۲ formulation demonstrating an optimal balance between stiffness and flexibility. Swelling analysis in ۰.۹% NaCl solution showed that moderate PVA incorporation produced controlled fluid uptake, suggesting an inverse correlation between network density and water absorption capacity. Antimicrobial activity evaluated against Staphylococcus aureus and Escherichia coli demonstrated concentration-dependent inhibition, with the scaffold containing ۱.۵ g gambier extract exhibiting the most homogeneous inhibition behavior and more uniform antibacterial distribution. The findings indicate that polymer network densification and phenolic–polymer interactions play a critical role in modulating mechanical reinforcement, swelling kinetics, and diffusion-mediated antimicrobial performance. Collectively, the optimized PVA–starch–gambier scaffold exhibits integrated structural and functional characteristics suitable for potential wound dressing applications. These findings highlight the important role of polymer–polyphenol interactions and crosslinking chemistry in designing multifunctional sustainable materials.

کلیدواژه ها:

PVA-starch composite scaffold ، Citric acid crosslinking ، Swelling behavior ، Gambier extract ، Antimicrobial wound dressing