Targeting collagen damage for sustained in situ antimicrobial activities

Antimicrobial peptides (AMPs) are promising anti-infective drugs, but their use is restricted by their short-term retention at the infection site, non-targeted uptake, and adverse effects on normal tissues. Since infection often follows an injury (e.g., in a wound bed), directly immobilizing AMPs to the damaged collagenous matrix of the injured tissues may help overcome these limitations by transforming the extracellular matrix microenvironment of the infection site into a natural reservoir of AMPs for sustained in situ release. Here, we developed and demonstrated an AMP-delivery strategy by conjugating a dimeric construct of AMP Feleucin-K3 (Flc) and a collagen hybridizing peptide (CHP), which enabled selective and prolonged anchoring of the Flc-CHP conjugate to the damaged and denatured collagen in the infected wounds in vitro and in vivo. We found that the dimeric Flc and CHP conjugate design preserved the potent and broad-spectrum antimicrobial activities of Flc while significantly enhancing and extending its antimicrobial efficacy in vivo and facilitating tissue repair in a rat wound healing model. Because collagen damage is ubiquitous in almost all injuries and infections, our strategy of targeting collagen damage may open up new avenues for antimicrobial treatments in a range of infected tissues.