AgNPs-immobilized carbon sphere from thiol-modified cellulose nanocrystal for enhancing antibacterial property of...

Although silver nanoparticles (AgNPs) have the effective antibacterial property, its application was limited by the accumulated toxicity. It was necessary to develop a carrier material to immobilize AgNPs. In this study, for the first time, thiol-modified carbon spheres (TMCS) were synthesized by hydrothermal method, which was used to immobilize AgNPs. It effectively solved the problem of cumulative toxicity. Thiol-modified carbon spheres loaded with silver nanoparticles (TMCS@Ag) were then blended with pulp fibers to prepare antimicrobial composite paper. The addition of TMCS@Ag changes the internal microstructure of the paper, improves its mechanical properties and thermal stability, and at the same time reduces solubility and swelling, which is conducive to use and preservation. It is worth noting that due to the immobilization of TMCS and the wrapping effect of paper fibers, the cumulative release of Ag⁺ in the composite paper reached only 5.15 % on the 14th day, and the cell survival rate was >95 % after co-culture, which proves that the release rate was controlled and the cumulative toxicity of AgNPs was effectively reduced. Nevertheless, the composite paper still has good antimicrobial properties against E. coli and S. aureus. Therefore, this study provides a new strategy for the safe application of antibacterial paper in food preservation, medical and health fields.