Cottonwood Honey (Ceiba pentandra) as Bioreductor for Preparation of AgNPs-mediated Chitosan-based Hand Gel Sanitizer

Antimicrobial resistance is a critical issue where microorganisms develop resistance to the drugs intended to control them, thus posing a significant threat to global health. Silver nanoparticles (AgNPs) have various types of antibacterial mechanisms that can effectively overcome this problem. In this work, AgNPs were modified with water-soluble chitosan (oligochitosan) obtained by depolymerizing low molecular weight chitosan as a stabilizer to enhances the antibacterial activity of the nanoparticles. The synthesis of AgNPs was carried out through an environmentally friendly approach by mixing 0.1 M AgNO₃ with 3% cottonwood honey solution as a bioreductor for formulating a nonalcoholic hand sanitizer. The mixture was exposed to sunlight at temperatures between 26°C to 35°C with an intensity of 88,400-137,600 lux for 10 minutes. UV-Vis spectroscopic analysis showed a broad peak in the wavelength range of 330-550 nm, with the highest peak recorded at 450 nm. In the antibacterial activity test of the hand sanitizer gel containing AgNPs-mediated chitosan at concentrations of 5%, 7.5%, 10%, and 12.5%, the inhibition zones observed against Staphylococcus aureus bacteria were 12.58 mm, 14.35 mm, 14.66 mm, and 17.14 mm, while for Pseudomonas aeruginosa bacteria the inhibition zones were 11.41 mm, 12.33 mm, 12.99 mm, and 13.63 mm, respectively. AgNPs-mediated chitosan-based hand gel sanitizer demonstrates superior antibacterial efficacy compared to traditional 70% alcohol-based hand sanitizers. This innovative solution offers an alternative to continuous alcohol use, which can cause skin irritation, while also addressing concerns related to antimicrobial resistance.