Zwitterionic nanoplasmonic bio-meshes for in situ spatiotemporal SERS monitoring of Pseudomonas aeruginosa biofilms

Abstract Biofilms, notorious for their recalcitrance and dynamic behavior, pose a persistent threat to public health. However, existing diagnostic tools fall short in providing in situ, spatiotemporal biochemical insights into dynamic biofilm behavior. To address this, we have developed zwitterionic nanoplasmonic bio-meshes that combine the antifouling attributes of zwitterionic L-cysteine, the biocompatibility of polymeric meshes, and the ultrasensitive, uniform, and stable surface-enhanced Raman spectroscopy (SERS) response of plasmonic nanocavity arrays. This platform delivers improved SERS performance in human serum compared to controls without L-cysteine functionalization, achieving a clinically-relevant limit of detection of 5.6 nM for pyocyanin in undiluted human serum. Moreover, the platform enables real-time, in situ spatiotemporal SERS monitoring of P. aeruginosa biofilms over 48 h in culture media-agar backgrounds, revealing distinct pyocyanin secretions dynamics in wild-type and hyperbiofilm mutant strains. We envision that this capability to non-invasively monitor biofilm metabolite secretion dynamics can empower next-generation biofilm diagnostics and anti-biofilm therapies.