Biological Activity of Irradiated Amniotic Membrane Extract with Zinc Oxide Nanoparticles in the Treatment of Atopic Dermatitis-Associated Bacteria: In Vitro Study

Abstract Atopic dermatitis (AD) hand lesions present a complex clinical challenge characterized by persistent microbial dysbiosis, severe cutaneous inflammation, unmitigated oxidative stress, and epidermal barrier breakdown. This study evaluated the therapeutic potential, clinical feasibility, and safety limits of a novel nano-bio-formulation combining Zinc Oxide Nanoparticles (\(\:\eta\:\text{ZnO}\)) and Irradiated Amniotic Membrane Extract (IAME) against multidrug-resistant (MDR) bacteria isolated directly from active AD hand lesions. Forty-five clinical isolates belonging to five predominant biofilm-forming species— Staphylococcus aureus , Staphylococcus epidermidis , Staphylococcus hominis , Staphylococcus warneri , and Kocuria rosea —were isolated and characterized. The 1:1 \(\:\eta\:\text{ZnO}\) + IAME co-formulation demonstrated potent, multi-targeted efficacy by eradicating established bacterial biofilms (up to \(\:92\%\) biomass reduction across \(\:n=33\) multidrug-resistant isolates), suppressing heat-induced bovine serum albumin protein denaturation (\(\:{\text{IC}}_{50}=81.65\:\mu\:\text{L/mL}\)), and exhibiting superior DPPH free-radical scavenging capacity (\(\:{\text{IC}}_{50}=15.65\:\mu\:\text{L/mL}\)) comparable to standard Ascorbic Acid (\(\:{\text{IC}}_{50}=17.14\:\mu\:\text{L/mL}\)). Cell culture evaluations on human dermal fibroblasts demonstrated that co-administering IAME attenuated \(\:\eta\:\text{ZnO}\)-induced cytotoxicity by \(\:>80\%\), maintaining cell viability near \(\:90\%\). Crucially, both the pharmacological \(\:{\text{IC}}_{50}\) values and the antimicrobial minimum inhibitory concentrations (\(\:\text{MIC}=12.5\text{--}25\:\mu\:\text{L/mL}\)) were substantially lower than the co-formulation's cytotoxicity \(\:{\text{IC}}_{50}\) threshold. This highlighting a safe, highly biocompatible, non-steroidal topical candidate capable of breaking the chronic infection–inflammation–oxidative stress cycle and restoring epidermal homeostasis in AD hand lesions.