Advanced hybrid nanomaterials based on carboxymethyl-modified biopolymer: Green synthesis and application in sustainable antimicrobial products

The utilization of agricultural by-products for the synthesis of hybrid nanomaterials represents an environmentally sustainable approach. This research aims to comprehensively investigate high-performance silver and copper nanoparticles hybrid materials based on carboxymethyl-modified cellulose / lignin derived from rice husks (CMC / CML-AgNPs and CMC / CML-CuONPs) and apply them for antimicrobial activities. CMC / CML was used to reduce Ag / Cu cations to the atomic level and then efficiently stabilize Ag / CuO nanoparticles, an eco-friendly method and sustainable development. The hybrid nanomaterials were successfully synthesized with spherical shapes and particle sizes ranging from 4 to 16 nm. The diffraction peaks at 38.46°, 46.57°, 64.93°, and 77.55° were ascribed to the face-centered cubic crystal lattice (111), (200), (220), and (311) of silver nanoparticles in the CMC / CML-AgNPs. The peaks were 32.26°, 46.06°, 52.16°, 61.71°, 63.80°, and 71.23° associating with the (110,20-2), (112), (11-3), (310), and (221) plane orientations of CuO nanoparticles. The proposed materials demonstrated highly efficient antimicrobial performances. Particularly, CMC-AgNPs and CML-CuONPs exhibited an inhibitory capability of up to 100 % against E. coli and S. aureus within 72 h. Simultaneously, the antifungal results showed that hybrid nanomaterials have a better ability to inhibit the A. niger than A. flavus fungus. When experimenting on peanut seeds, hybrid nanomaterials showed an inhibitory capability of up to 99.0 % against A. niger. IC₅₀ values of the hybrid nanomaterials range from 0.872 mg/mL to 1.188 mg/mL, confirming that these materials are non-cytotoxic. These materials exhibit significant stability and enduring antimicrobial efficacy, making them ideal for sustainable development of various antibacterial and antifungal blocks for the near future.