Non-lytic M13 phage-based highly sensitive impedimetric cytosensor for detection of coliforms

Publication date: Available online 22 October 2019Source: Biosensors and BioelectronicsAuthor(s): Mohammed Sedki, Xingyu Chen, Chuan Chen, Xin Ge, Ashok MulchandaniAbstractA highly sensitive and selective non-lytic M13 phage-based electrochemical impedance spectroscopy (EIS) cytosensor for early detection of coliforms is introduced for the first time. AuNPs were electrochemically deposited on the surface of glassy carbon electrode, and the M13 phage particles were immobilized on them using 3-mercaptopropanoic acid linker and zero-length crosslinking chemistry (EDC/NHS). Next, the sensor surface was blocked to avoid non-specific binding. The M13-EIS cytosensor was tested for detection of F+ pili Escherichia coli species, using XL1-Blue and K12 strains, as examples of coliforms. The selectivity against non-host strains was demonstrated using Pseudomonas Chlororaphis. The binding of E. coli to the M13 phage on the cytosensor surface increased the charge transfer resistance, enabling detection of coliforms. The biosensor achieved a limit of detection (LOD) of 14 CFU/mL, the lowest reported to-date using EIS-phage sensors, and exhibited a high selectivity towards the tested coliforms. The SEM micrographs confirmed the successful capturing of E. coli on the M13-based EIS cytosensor. Moreover, the sensor showed almost the same sensitivity in the simulated river water samples as in phosphate buffer, reflecting its applicability to real samples. On the other hand, this sensor system...
Source: Biosensors and Bioelectronics - Category: Biotechnology Source Type: research