Effects of <scp>CuO</scp> nanoparticles on the physical and functional properties of biodegradable polymer‐based composites for biomedical and flexible packaging applications

Abstract This study explores the development of biodegradable nanocomposites using HPMC, PVA, and CMC, incorporated with copper oxide (CuO) nanoparticles, aiming to create sustainable packaging materials with improved antimicrobial properties. CuO nanoparticles were synthesized via a chemical precipitation method and integrated into the polymer blend through a casting technique. X‐ray diffraction (XRD) analysis confirmed the monoclinic crystal structure of CuO and the semi‐crystalline nature of the polymer blends. Fourier transform infrared (FTIR) spectroscopy revealed interactions between the host polymers and CuO nanoparticles. Optical tests showed that the addition of CuO nanoparticles reduced both the direct (E gd ) and indirect (E gi ) energy gaps. Electrical conductivity measurements indicated an increase in conductivity with higher CuO concentrations, attributed to enhanced charge carrier mobility and reduced crystallinity. Contact angle measurements indicated decreased hydrophobicity as CuO concentration increased, suggesting improved biocompatibility. Cell viability tests on HFB4 fibroblast cells demonstrated a significant increase in cell viability, with the highest value observed at 5.0 wt% CuO, indicating favorable biocompatibility for biomedical applications. Moreover, antimicrobial testing revealed significant inhibition against both Gram‐positive and Gram‐negative bacteria, with a stronger effect on Gram‐positive strains. These results highlight the potential of CuO nanoparticles in enhancing the properties of HPMC/PVA/CMC blends, offering promising applications for biodegradable packaging materials, electronic devices, and biomedical fields. Highlights Biodegradable HPMC/PVA/CMC films enhanced using CuO for eco‐friendly use. CuO nanoparticles improved optical and electrical properties by reducing band gaps. Enhanced antimicrobial activity observed against Gram‐positive bacteria. Biocompatibility confirmed, with 5.0 wt% CuO showing the best performance. Developed films are promising for biomedical uses and sustainable packaging.