Antibacterial efficacy of low-dosage silver nanoparticle–sodium alginate–chitosan nanocomposite films against pure and clinical acne strains

Abstract

The silver nanoparticles–sodium alginate–chitosan (AgNPs–Alg–Chi) nanocomposite film is a compelling material with demonstrated antibacterial efficacy against various pure bacterial strains. However, its potential cytotoxicity at elevated Ag doses warrants investigation. There is a notable dearth of studies assessing its antibacterial effectiveness against clinically relevant bacterial strains, notably Cutibacterium acnes. This study aims to assess the antibacterial efficacy of the low-dose AgNPs–Alg–Chi nanocomposite films on both pure bacterial strains and strains isolated from clinical samples obtained from 65 acne patients. The films were synthesized using green methods, incorporating kumquat (Citrus japonica) extract as a silver ion-reducing agent. The material characterization methods include UV-Vis and FTIR spectroscopies, SEM-EDS, XPS, cell culture, and MTT assay. We successfully fabricated the AgNPs–Alg–Chi nanocomposite films with a low-loading dose of Ag NPs (≤11 μg mL⁻¹, and 37.8 ± 11.5 nm in size). The AgNPs–Alg–Chi nanocomposite film demonstrated comparable antibacterial efficacy to the AgNPs–Chi solution, with MIC values ranging from 3.67 to 5.50 μg mL⁻¹ (p > 0.05) across all strains. Importantly, the AgNPs–Alg–Chi films demonstrated excellent biocompatibility with human keratinocytes (HaCaT cells), maintaining cell viability above 70%. The present AgNPs–Alg–Chi nanocomposite films synthesized by a green approach demonstrated potent antibacterial activity, making them promising for further development into suitable products for human use.