Invisible shield: Sprayable supramolecular antimicrobial microscale films for preventing wound and medical device infections

Abstract Wound and device-associated infections remain difficult to eradicate because biofilms block host immunity and antibiotics, accelerating chronicity and resistance. Here, we present a portable, low-cost dual-syringe spray that deposits an ultra-thin, self-assembling antimicrobial film directly on wounds and implant surfaces. The device co-delivers oppositely charged hyaluronic acid (HA) and a cationic antimicrobial peptide (polyarginine, PAR30), which rapidly form a conformal nanometric polyelectrolyte complex at the tissue-material interface. Molecular dynamics simulation revealed pronounced positional heterogeneity within the PAR30/HA complex and identified an N-terminal arginine as a dominant interaction hotspot. The resulting coating adheres to diverse substrates, kills bacteria on contact, prevents biofilm formation, and sustains antimicrobial efficacy. Across vitro assays and murine wound infection models, treatment produced 4 to 5 log reductions in bacterial burden against methicillin-resistant Staphylococcus aureus and Gram-negative pathogens, including Pseudomonas aeruginosa and Escherichia coli . The formulation is biocompatible, did not increase cutaneous inflammation or IL-6 levels in vivo , and reduced post-surgical pain and motor deficits in a mouse incision model. To our knowledge, this is the first antimicrobial treatment system applicable to both tissues and medical devices. Developed under a safe-and-sustainable-by-design approach, this technology combines biocompatible components, nanometric coating for minimal material use, and a simple syringe-based delivery device, offering a scalable, antibiotic-free strategy for wound care and medical device infection prevention. Graphical abstract