Tunning of the antimicrobial activity of surgical sutures coated with silver nanoparticles

Silver nanoparticles capped with sodium alginate were deposited layer-by-layer on surgical sutures and characterized for their anti-microbial activity against Staphylococcus aureus. The concentration of sodium alginate used in the synthesis step was varied from 5 mM to 0.1 mM and was found to have a major effect on the final antimicrobial activity of the fiber. The layer-by-layer deposition of the silver nanoparticles with poly (diallyldimethylammonium chloride) was first studied on glass slide by monitoring the changes in absorbance at 400 nm which correspond to the plasmon band of the silver nanoparticles. The layer-by-layer deposition process was concluded from the linear increase in film absorbance as a function of the number of deposited layers. The same deposition technique was then applied to the polyamide surgical sutures and the lowest alginate concentration produced the highest antimicrobial efficiency. These results suggest that the tuning of the capping used in the synthesis step strongly influence the later antimicrobial activity of the nanoparticles.