In Vivo Two-Way Redox Cycling System for Independent Duplexed Electrochemical Signal Amplification.

An in vivo two-way redox cycling system based on whole-cell bidirectional electron transfer was developed and applied for independent duplexed electrochemical signal amplification. This duplexed signal amplification system was established by activating the bacterial "inwards" electron transfer at low electrode potential for oxidative cycling, while accomplishing the bacterial "outwards" electron transfer at high electrode potential for reductive cycling. Therefore, with this two-way bioredox cycling system, simultaneous and independent amplification of the electrochemical signals for oxidation and reduction was achieved. More impressively, by using this duplexed signal amplification system, ultrasensitive and simultaneous detection of two different warfare toxins of Pseudomonas aeruginosa was achieved (sensitivity was improved 302 and 579 times, respectively), which makes it possible for double-checking early diagnosis of the P. aeruginosa infections.