Antimicrobial activity of silver nanoparticles encapsulated in poly-<em>N</em>-isopropylacrylamide-based polymeric nanoparticles

Abstract

In this study, we analyzed the antimicrobial activities of poly-<i>N</i>-isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH₂-based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO₃ using NaBH₄ as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative (<i>Escherichia coli</i>) and Gram-positive (<i>Staphylococcus aureus</i>) bacteria depending on the nanoparticle size and amount of AgNO₃ used during fabrication.