Effect of silver and copper nanoparticles on adsorption and fluorescence of tryptophan on the surface of bactericidal textile

Biomedical preparations based on cotton tissue modified with nanoparticles of silver and copper with pronounced bactericidal properties have been obtained. The bactericidal activity of Ag- and Ag/Cu-modified cotton fabrics (assessed by the inhibition zone of bacterial growth) was evaluated against bacteria E. coli , K. pneumonia , P. aeruginos , S. aureus, E. faecalis . To suppress a toxic effect of nanoparticles we investigate the possibilities of adsorption modification of cotton fabrics contained Ag and Ag/Cu nanoparticles by amino acid tryptophan (Trp) and the effect of metals on Trp fluorescence spectra. Adsorption isotherms of Trp demonstrate a significantly higher adsorption capacity of Ag/Cu/cotton compared to Ag/cotton. The fluorescence of Trp is quenched on the modified tissue surfaces due to the formation of complexes with silver and copper ions, released from the metal nanoparticles. It is shown that the complexation of copper and silver nanoparticles with Trp on the surface of tissues does not reduce their bactericidal action against a number of microorganisms.