Antimicrobial Biocomposites Fiber-Welded with Lignocellulose Containing Silver Nanoparticles

Biopolymer materials that use silver to imbue antimicrobial properties are finding broad application in areas such as packaging, textiles, and building materials. Conventional methods to incorporate silver can damage the supporting biopolymer matrix and/or result in large-sized silver nanoparticles (Ag NPs) with poor antimicrobial efficacy. To mitigate these concerns, in this study, uniformly distributed, small (approximate to 5-10 nm) Ag NPs are grown into a well-preserved lignocellulose powder matrix by using a gas-phase reducing agent at low temperature. The Ag NP- lignocellulose powders are fully characterized and their antimicrobial performance is investigated by inactivating planktonic bacteria and inhibiting biofilms. The most potent antimicrobial product, L_10Ag, achieves more than 4-log reduction in planktonic bacterial viability within 3 h and a biofilm inhibition rate of 97.9%. Furthermore, the Ag NP impregnated powders are post-processed through natural fiber welding (NFW), an emergent, innovative, ionic liquid (IL)-based method that can be used to engineer biopolymer materials into new functional biocomposites. NFW transforms the powders into higher-order structures, imparting anti-microbial capacity without degrading the material properties of the biopolymer support.