Fatty amine-conjugated cellulose for microencapsulated antimicrobial bioactive systems: Synthesis, optimization, and biological assessment for fabric application

Abstract

This study reports the development of hybrid antimicrobial microencapsulation systems by integrating natural bioactive agents with biogenic metal ions into a fatty amine-conjugated cellulose matrix. Carboxymethyl cellulose (CMC) was chemically modified with oleylamine, a saturated fatty amine, to impart hydrophobicity and enhance compatibility with thyme essential oil. The oil was encapsulated within the modified cellulose to produce stable microparticles, which were further functionalized with silver ions via in situ chemical reduction, forming a biogenic ionic metal shell. This dual-functional system combines polymeric delivery and metallic antimicrobial action in a single platform, an approach that remains largely underexplored. The modified polymer was comprehensively characterized using FT-IR spectroscopy, thermal analysis, and SEC-HPLC. A definitive screening design (DSD) was employed to optimize the formulation parameters affecting particle size and emulsion stability. The optimized microparticles exhibited sizes ranging from 1.10 to 3.00 μm, with enhanced antimicrobial activity against Gram-positive and Gram-negative bacteria. Cytocompatibility assays using NIH-3 T3 fibroblasts confirmed ≥80 % cell viability after 24 h, supporting its safety for skin-contact materials. This work introduces an innovative, multifunctional platform suitable for pathogen-resistant textile and footwear applications, offering a sustainable and efficient approach to active fabric technologies.