Shape Memory PVA-Tannic Acid/CuO Nanocomposites for Microneedle Patches with Antibiofouling and Antioxidant Properties

Abstract

Shape memory materials capable of responding near physiological temperature are highly desirable for minimally invasive biomedical applications. However, achieving simultaneous mechanical robustness and biological functionality remains challenging. In this study, we developed a multifunctional CuO nanomaterial-reinforced poly(vinyl alcohol)-tannic acid (PVA-TA/CuO) nanocomposite as a temperature-responsive shape memory platform. PVA-functionalized CuO nanostructures with an average diameter of 200− 300 nm and lengths ranging from 0.5 to 1 μm were reinforced into a PVA-TA matrix through dynamic hydrogen bonding and Cu2+-polyphenol coordination interactions. The resulting composite exhibited improved structural stability, an enhanced tensile strength of 9.31 MPa, and a superior thermal stability compared with the PVA-TA composite. Notably, PVA-TA/CuO showed a rapid shape recovery at 40 °C, with dynamic mechanical analysis revealing a temperature-dependent relaxation transition at approximately 38 °C, supporting its near-physiological-temperature shape recovery. The PVA-TA/CuO composite also demonstrated significant antioxidant activity, excellent cytocompatibility, and pronounced antibiofouling behavior, achieving up to 83% and 75% biofilm inhibition against Escherichia coli and Staphylococcus aureus, respectively. Furthermore, PVA-TA/CuO was successfully fabricated into a mechanically robust microneedle patch with sufficient insertion capability. Overall, our results highlight that nanoscale CuO reinforcement is an effective strategy for engineering mechanically robust, temperature-responsive shape memory materials with multifunctional properties for advanced biomedical applications.