A new biosensor based on the recognition of phages and the signal amplification of organic-inorganic hybrid nanoflowers for discriminating and quantitating live pathogenic bacteria in urine

Rapid and accurate detection of live pathogenic bacteria in urine is indispensable for the diagnosis of urinary tract infection (UTI) in clinical practice. In the present study, an electrochemical biosensor was developed to quantify live bacteria in urine accurately and rapidly, by taking Escherichia coli (E. coli) as an example. The main strategy was based on the specific recognition of T4 phages and the signal amplification of organic-inorganic hybrid nanoflowers (GOx&HRP-Cu3(PO4)2). After connecting the thionine, the signal was gradually amplified with the cascade effect of three redox reactions. Using this proposed electrochemical biosensor, live E. coli can be quantified at a linearity range of 15-1.5 × 108 CFU/mL, with a very low detection limit of 1 CFU/mL. Compared with the traditional method of culturing and counting, the present biosensor is easier and simpler to handle, and the process of quantitation was completed within only 140 min. Present results showed that the proposed electrochemical biosensor has great potential application in diagnosing and monitoring UTI in clinical settings.