Developing a lyophilized cell-free biosensor for rapid diagnostics of clinical Pseudomonas aeruginosa infections

Abstract:

[Objective] Pseudomonas aeruginosa is a Gram-negative bacterium prevalent that is conditionally pathogenic and commonly associated with nosocomial infections. Its quorum sensing signal, 3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL), has been reported as a biomarker for its infection. Here, we aimed to develop a 3OC12-HSL biosensor for facilitating rapid diagnostics of clinical P. aeruginosa infections. [Methods] We constructed a reporter plasmid responsive to 3OC12-HSL and prepared a lyophilized cell-free biosensor based on that plasmid. We characterized the biosensor with 3OC12-HSL concentration gradient, validated its utility by testing clinical samples, and attempted to optimize the preprocessing procedure for clinical samples.[Results] Our cell-free biosensor is sensitive, specific, and capable of diagnosing P. aeruginosa infections in clinical respiratory samples within 60 min.[Conclusion] In this study, we developed a lyophilized cell-free 3OC12-HSL biosensor. By pre-expressing RNase inhibitor, we increased our biosensor's tolerance to body fluid, and further demonstrated its potential to be developed as a rapid diagnostic method for clinical P. aeruginosa infections.