Bioorthogonal Anchor-and-Lock of Probiotic Biofilms on Diverse Biomaterials to Combat Delayed Implant-Associated Infection.

Abstract

Bacterial adhesion and biofilm formation on implants remain a leading cause of device failure, and delayed-onset infections become refractory to antibiotics once mature biofilms form. Probiotic biofilms offer a promising alternative to conventional antimicrobial coatings, but clinical translation is hindered by the lack of a stable, substrate-generalizable immobilization method. Here we presented a broadly applicable "anchor-and-lock" strategy that covalently tethered probiotic biofilms to diverse implants via bioorthogonal SPAAC reaction. A mussel-inspired adhesive peptide functionalized with DBCO served as the surface anchor, while L. casei metabolically labeled with azide groups became the click-ready lock. The resulting coatings formed uniformly on titanium, polyurethane, silicone rubber, and polypropylene, exhibiting long-term stability. The biofilm operated through a dual-phase antimicrobial mechanism, including an initial bactericidal phase (≥96% killing of S. aureus) mediated by lactic acid and hydrogen peroxide release, followed by a sustained anti-adhesive phase that prevented pathogen colonization. RNA-sequencing revealed that the coating downregulated S. aureus adhesion-associated genes while suppressing carbohydrate transport and metabolic pathways. In clinically relevant delayed-infection models in bone and bladder, functionalized implants prevented infection, mitigated inflammation, and promoted tissue integration, effects absent on unmodified controls. This SPAAC-mediated strategy offers a broad approach to mitigating implant-associated infections.