Ultrafast detection of infectious bacteria using optoelectronic nose based on metallic nanoparticles

Abstract

Developing an accurate and sensitive method for detection of waterborne pathogens and urinary tract infection are important environmental and clinical challenges. We report a colorimetric assay based on arrays of nanoparticles for identification of 10 infectious bacteria strains belonging to both gram positive and gram-negative species. The detection system works based on the interaction of the volatile metabolites emitted from bacteria with the arrays of metallic nanoparticles deposited on paper substrate. The color changes, monitored by a flatbed scanner, are analyzed by statistical pattern recognition methods. A unique colorimetric pattern is achieved for each bacteria strain. We could detect bacteria at very low concentrations (around 100 bacteria/mL) in less than 10 min, which is the fastest method reported ever. The sensor can be used successfully for detection of bacteria in drinking water as well as human urine (containing 177 healthy and 123 patient samples) in less than 50 min, which is dramatically faster than urine culture. The provided detection system opens a new way to develop simple, small, sensitive and rapid devices for detecting pathogens in various clinical samples.