Engineering CMC-Templated AgNP-Filled EPDM Composites with Controlled Release for Enhanced Antimicrobial Performance and Cytocompatibility

Balancing antimicrobial efficacy with cytocompatibility remains a persistent challenge in elastomeric materials. Herein, this study addressed the gap by engineering AgNP-filled EPDM composites in which nanoparticle loading and network architecture were jointly tuned to achieve selective bioactivity. Carboxymethyl cellulose (CMC) and AgNPs were incorporated into EPDM, and the systems were examined in unvulcanized and vulcanized states to elucidate the role of cross-linking on release, performance, and safety. Physicochemical characterization, rheological and mechanical evaluation, swelling analysis, and kinetic release modeling were conducted alongside agar diffusion, CFU counting, and MTT assays. The results demonstrated a synergistic enhancement in antimicrobial activity with increasing AgNP content, while vulcanization stabilized the polymer network and promoted effective incorporation of the AgNPs within the EPDM matrix. Silver release followed diffusion-controlled kinetics, enabling sustained activity. Notably, vulcanized composites exhibited rigorous antimicrobial performance while maintaining lower cytotoxicity. Therein, microbial inhibition was governed by surface-mediated interactions, whereas cytocompatibility was controlled by bulk leaching behavior. All formulations remained within acceptable cytotoxic limits, validating their biological safety. This work established a scalable and versatile strategy to decouple antimicrobial potency from cytotoxic response through controlled network design. The developed materials, therefore, offer promising potential for protective and sportswear applications requiring durable, safe, and long-lasting antimicrobial functionality.