Non-covalent co-assembly of gallic acid and antimicrobial peptides for long-lasting antibacterial coatings via interfacial engineering

The widespread demand for eco-friendly, long-lasting antimicrobial materials in food packaging and medical settings remains unmet due to the limitations of conventional coatings, which often suffer from poor water resistance, environmental toxicity, and short-term efficacy. Herein, a facile interfacial engineering strategy is reported to construct long-lasting antibacterial films via non-covalent co-assembly of gallic acid (GA) and antimicrobial peptides (AMPs). Three AMPs (G3, C12, C16) with varied structural features and hydrophobic domains are chosen to synergize with GA through hydrogen bonding, electrostatic interactions, and hydrophobic effects, forming insoluble aggregates. These aggregates are uniformly coated onto polyethylene terephthalate (PET) surface, yielding a robust network structure with strong adhesion, which can serve as a reservoir to release AMPs gradually. The PET surface modified with GA/AMPs achieves > 90 % inhibition rates against Escherichia coli and Staphylococcus aureus, attributed to membrane disruption via released AMPs. Remarkably, the coatings retain 80 % antibacterial efficacy even after two days of rigorous water washing, demonstrating superior durability. Cytotoxicity assays reveal high cell viability for both HepG-2 and CHO cells, underscoring excellent biocompatibility. This work presents a scalable, energy-efficient approach to fabricate wash-resistant antimicrobial coatings, offering promising potential for next-generation food packaging and biomedical applications.