Antibacterial effects of in situ zinc oxide nanoparticles generated inside the poly (acrylamide-co-hydroxyethylmethacrylate) nanocomposite

Abstract The present work reports the antibacterial activity against Pseudomonas aeruginosa of a nanocomposite made of zinc oxide nanoparticles dispersed in a poly(acrylamide-co-hydroxyethylmethacrylate) matrix (PAAm-Hema-ZnONPs). The in situ synthesis of ZnONPs inside of the PAAm-Hema crosslinked network is described. Moreover, the physicochemical properties of the PAAm-Hema-ZnONPs nanocomposite are analyzed. The results confirm that the PAAm-Hema hydrogel provides an excellent scaffold to generate ZnONPs. The presence of ZnONPs inside the hydrogel was confirmed by UV–visible (band at 320 nm), by Infrared spectroscopy (peak at 470 cm⁻¹), SEM, and TEM images. The presence of NPs in PAAm-Hema diminish the swelling percentage by 70%, and the Young modulus by 33.7%, compared with pristine hydrogel. The 75% of ZnONPs are released from the nanocomposite after 48 h of spontaneous diffusion, allowing the use of the nanocomposite as an antibacterial agent. In vitro, the agar diffusion test presents an inhibition halo against P. aeruginosa bacteria 50% higher than the unloaded hydrogel. Also, the PAAm-Hema-ZnONPs live/dead test shows 54% of dead cells more than the hydrogel. These results suggest that the easy, one-step way generated composites can be used in biomedical applications as antimicrobial agents.