Facile preparation of L-ascorbic acid-stabilized copper-chitosan nanocomposites with high stability and antimicrobial properties

Highly stable dispersions of nanosized copper (Cu) particles with an average size of (2.6 ± 0.5) nm were synthesized by in situ reduction of Cu(II) to immobilize Cu nanoparticles on the amino-enriched surface of chitosan (CTS). The synthetic process and stability of the l-ascorbic acid-stabilized Cu-CTS nanocomposites were investigated by X-ray photoelectron spectroscopy and Fourier transform Infrared spectroscopy. The antimicrobial efficiency and potency of the Cu-CTS nanocomposites were studied. The Cu-CTS nanocomposites were found to exhibit a broad antimicrobial spectrum and high antimicrobial activity against Gram-positive bacterial pathogen Staphylococcus aureus and fungal pathogen Monilia albican. The minimum inhibitory concentration of the Cu-CTS nanocomposites toward S. aureus was found to be 6.4 μg mL−1, much lower than those reported in the literature. Furthermore, the Cu-CTS nanocomposites were stable and maintained good disinfection potential even after 90-day shelf-time under ambient conditions.