Hybrid PVA filaments with combined release-based and contact-active antimicrobial functionality: Structure, release,...

Localized antimicrobial functionality in biomedical materials requires both rapid microbial suppression and sustained long-term protection, which are difficult to achieve simultaneously with conventional systems. Here, we present a dual-mode antimicrobial design strategy integrating release-based and contact-active mechanisms within a single platform. In this study, hybrid poly(vinyl alcohol) (PVA) filaments combining gentamicin sulfate (GES) as the drug-loaded phase and zinc oxide (ZnO) nanoparticles as the inorganic antimicrobial phase were developed via melt extrusion as a scalable and shapeable platform (PVA-ZnO-GES), and their key structural, mechanical, release, antimicrobial, and biological properties were comparatively evaluated against single-phase counterparts (PVA-GES and PVA-ZnO). Structural and morphological analyses confirmed successful incorporation of both phases, while the hybrid system exhibited a balanced mechanical response. Release studies showed a pronounced burst for the drug-loaded system (∼49% within 1 h), which was reduced in the hybrid (∼14.9%), with comparable cumulative release after 24 h, indicating controlled early-stage release behavior. Antimicrobial evaluation against Escherichia coli, Staphylococcus aureus, and Candida albicans revealed distinct profiles: rapid but spectrum-limited activity for the drug-loaded system and slower yet sustained activity for the inorganic system. The hybrid system integrated these complementary behaviors, achieving rapid initial inactivation and complete elimination of microbial populations maintained over 21 days. Short-term analysis (0-24 h) further revealed a biphasic inactivation profile, with an early fast phase achieving 3-log reduction within <2.5 h. Cytocompatibility studies demonstrated high cell viability, supporting the suitability of the developed filaments for biomedical applications. Overall, these findings demonstrate that hybrid PVA-ZnO-GES filaments provide a versatile platform for combining controlled drug release with sustained antimicrobial functionality for biomedical applications.