Rapid and sensitive detection of Salmonella based on microfluidic enrichment with a label-free nanobiosensing platform

Abstract

Urinary tract infections are among the most common bacterial infections in humans, causing relapses and acute prostatitis as well as significant morbidity and high medical costs. In bacteria with low abundance in urological samples, which contain various contaminating factors, sample analyses should be conducted with meticulous care; therefore, emerging technologies can facilitate the characterization of disease-causing bacteria with more sensitivity, rapidity, and ease of use. In this study, we developed a highly sensitive nanobiosensor based on isothermal amplification combining microfluidic enrichment using a concanavalin A–functionalized microchannel with asymmetric herringbone groove arrays for rapid detection of pathogens. After optimization of enrichment and detection conditions, we demonstrated that Salmonella enterica serotype Typhimurium could be detected in urine samples (10 mL) at a concentration as low as 5 CFU/mL in real-time using a label-free method. Moreover, the use of microfluidic enrichment improved the sensitivity by 1.76 orders of magnitude. The whole experiment was completed within 100 min. This developed method has the potential to provide a simple, rapid, sensitive diagnostic platform and can be used in practical applications for detection of Salmonella or other pathogenic bacteria, causing urinary tract infections.