Chromium Cross-Linking Based Immobilization of Silver Nanoparticle Coating on Leather Surface with Broad-Spectrum Antimicrobial Activity and Durability.

Leather with durable and broad-spectrum antimicrobial properties is very attractive in applications to produce diabetic shoes. In this work, gallic acid stabilized silver nanoparticles (GA@AgNPs) were prepared as water-borne finishing agent to be spray-coated on leather surface, with subsequent immobilization onto skin collagen via chromium(III) cross-linking. Such chemical anchoring of AgNPs onto microscaled collagen fibers not only enhanced the hydrophobicity of leather surface but also converted the surface ζ-potential from a positive charge to a negative charge, resulting in the excellent microbial antiadhesive ability of GA@AgNP-coated leather because of its dual-hydrophobic and electrostatic repelling of microbial adhesion. Such GA@AgNP coating also exhibited broad-spectrum antimicrobial activity against Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus, and Candida albicans, with killing efficiencies all higher than 99%. Moreover, the killed microbes could be easily released from this anionic GA@AgNP spray coating by simply washing, preserving, and giving long-term antimicrobial activity to leather products. Most of all, the robust immobilization of AgNPs guaranteed the durably antimicrobial activity of such GA@AgNP-coated leather against laundry, perspiration, and mechanical abrasion in real daily use.