A Mechanistic, Architecture-Dependent Study Combining Experiments and Molecular Dynamics to Explain AMP Release from GO–PEI Coatings

This study investigates two graphene oxide (GO)-based coating architectures on urinary catheter substrates-layered (PEI+GO) and embedded (PEI/GO)-loaded with antimicrobial peptides (E14LKK and fLFB), with the aim of elucidating how coating structure governs peptide retention and release. Physicochemical and morphological characterization confirmed distinct coating architectures and thicknesses. Molecular dynamics simulations were employed to probe GO-peptide and PEI-peptide interactions, revealing weaker binding of fLFB to GO relative to PEI, consistent with enhanced peptide mobility. Antibacterial performance against <i>Escherichia coli</i> and <i>Enterococcus faecalis</i> was evaluated using agar diffusion assays as a comparative indicator of peptide release from surface-bound coatings. The layered PEI+GO-fLFB system exhibited the highest antibacterial activity, in agreement with simulation-predicted interaction energetics and structural fluctuations. Rather than targeting immediate clinical translation, this work provides mechanistic insight into how GO-polymer architecture modulates antimicrobial peptide availability, offering a molecular dynamics simulation-guided framework for the rational design of peptide-releasing antimicrobial coatings.