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

Wound and device-associated infections remain difficult to eradicate because biofilms limit host immunity and antibiotic efficacy, promoting chronicity and resistance. Here, we present a portable, low-cost dual-syringe spray that deposits a thin, self-assembling antimicrobial film directly on wounds and implant surfaces. The device co-delivers oppositely charged hyaluronic acid (HA) and polyarginine (PAR30), a cationic antimicrobial peptide, which rapidly assembles into a conformal micrometric polyelectrolyte complex at the tissue-material interface. Molecular dynamics simulations revealed 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. The treatment exhibited broad-spectrum in vitro activity against Gram-positive and Gram-negative pathogens, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In murine wound infection models, the spray coating significantly reduced MRSA bacterial burden. The formulation was biocompatible, did not increase cutaneous inflammation or IL6 levels in vivo, and reduced post-surgical pain and motor deficits in a mouse incision model. Developed within a safe-and-sustainable-by-design framework, this technology offers a scalable, antibiotic-free strategy for wound-care and medical-device infection prevention.