A new B-PAn-P system for the detection of bacteria population

A new base-type polyaniline piezoelectric bacteria culture (B-PAn-P) system for rapid detection of bacteria population was proposed. In this system, interdigital electrode coated with a base-type polyaniline/poly vinyl alcohol (B-PAn/PVA) composite film was used as probe (B-PAn probe) in place of steel electrode in multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. B-PAn/PVA film can react with CO2 produced by the growth of bacteria in culture medium, which caused the film electrical properties change. This change can be sensitively monitored by piezoelectric detection system. The superiority of using proposed probe instead of steel electrode were: firstly, it was more sensitive to bacteria growth response and secondly, it did not require a specially formulated culture medium which was demanded in MSPQC system. Just like MSPQC, proposed system can be used to detect bacteria population. When used to quantitatively determine Pseudomonas aeruginosa, the frequency detection time (FDT) obtained in frequency shift curve had a linear relationship with the logarithm values of initial concentration of P. aeruginosa in the range of 10 to 106 cfu ml−1. The detection limit was 10 cfu ml−1. Compared with MSPQC system, proposed system was more sensitive and no special demand to culture medium.