Approaching intelligent infection diagnostics: Carbon fibre sensor for electrochemical pyocyanin detection

Pyocyanin is produced by Ps. aeruginosa as a result of quorum sensing during wound colonisation increasing bacterial virulence and damaging host physiology, both of which contribute to an increased risk of infection. The use of carbon fibre tow as an electrochemical sensing matrix for assessing pyocyanin production is evaluated. Prototype sensor assemblies have been developed and response characteristics towards pyocyanin are detailed. The sensitive and linear quantification of pyocyanin is presented (r2 = 0.998) across the biomedically relevant concentration range (1–100 µM). Precise electrochemical measurements of pyocyanin by square wave voltammetry are established using carbon fibre assemblies (coefficient of variance = 1.2 and 1.4% for 10 and 50 µM pyocyanin, respectively). Further testing of the sensors in bacterial cultures shows the ability to monitor pyocyanin production by Ps. aeruginosa in agreement with the chloroform-acid/photometric method and in the presence of other bacterially derived pigments and metabolites. The proposed small and inexpensive sensor assembly is suggested for use in monitoring Ps. aeruginosa growth.