Synthesis, characterization, shelf life and optimization of process parameter of plasma-activated hydrogel production for Staphylococcus aureus Inhibition

An investigation optimized plasma-activated hydrogel (PAH) as a chemical-free antimicrobial for Staphylococcus aureus on animal skin, targeting antibiotic resistance and chronic wounds. Plasma-activated water (PAW) generates reactive oxygen and nitrogen species (RONS) that provide chemical-free antimicrobial activity, while PAH extends stability and improves application to irregular wound surfaces. A factorial design evaluated PAW treatment time (0-20 min) and hydrogel ratio (1:5-3:5) on oxidation-reduction potential (ORP), electrical conductivity (EC), pH, and H₂O₂, with all tests in triplicate. Longer PAW exposure reduced ORP (385.97 to 278.90 mV) and lowered pH to 5.17, while both variables increased EC (up to 263.75 µS/cm), reflecting elevated reactive species and non-linear EC/ORP behavior. Optimal conditions were a 3:5 gel ratio with 20-minute PAW treatment, giving ORP 278.90 mV, EC 263.75 µS/cm, pH 5.325, and H₂O₂ 29.38 ppm. Kinetic studies showed slower H₂O₂ decay in PAH than in PAW, maintaining ~ 10.6 ppm after 4 weeks at refrigeration. Optimized PAH achieved approximately 9.5 log₁₀ CFU/mL S. aureus reduction, highlighting promising potential for veterinary wound care applications.