Efficient capture, rapid killing and ultrasensitive detection of bacteria by a nano-decorated multi-functional...

In this work, we demonstrated a nano-decorated porous impedance electrode sensor for efficient capture, rapid killing and ultrasensitive detection of bacteria. The multi-functional sensor was prepared by a facile sonochemical method via in situ deposition of antibacterial prickly Zn-CuO nanoparticles and graphene oxide (GO) nanosheets on a Ni porous electrode. Due to the surface burr-like nanostructures, the nano-decorated impedance sensor exhibited very good bacterial-capture efficiency (70 - 80% in 20min) even at a low concentration of 50 CFU mL^-1, rapid antibacterial rate (100% killing in 30min) and high detection sensitivity (as low as 10 CFU mL^-1). More importantly, the nano-decorated sensor has proven to be highly effective in quantitative detection of bacteria in a biological sample, for example, a rat blood sample spiked with E. coli. Despite the complexity of blood, the sensor still exhibited excellent detection precision within 30min at bacteria concentrations ranging from 10 - 10⁵ CFU mL^-1. The simplicity, rapidity, sensitivity, practicability and multifunctionality of this impedance sensor would greatly facilitate applications in portable medical devices for on-the-spot diagnosis and even the possibility for simultaneous therapy of diseases caused by bacterial infections.