Rapid detection of the Escherichia coli (E. coli) bacterium responsible for about 80% of urinary tract infections is now The smartphone-based microfluidic system quantifies E. coli in urine in less than 25 minutes. Source: University of Bath possible with a simple microfluidic system that works in concert with a smartphone. The diagnostic engineered at University of Bath, U.K., returns results in 25 minutes and offers a portable, accurate assay for deployment in resource-limited areas.

The optical, smartphone-based microfluidic fluorescence immunoassay quantifies E. coli in urine without the need for sample preparation or concentration. The sample passes through the plastic microfluidic device fitted with microcapillaries coated with capture antibody, which bind to the bacteria. Addition of an enzyme results in a subsequent color change, which is detected by the smartphone camera, and bacterial concentration is determined by analyzing an image from the camera.

Proof of concept tests with synthetic urine demonstrated E. coli recovery values, limits of detection and precision comparable to that for high-performance automated immunoassays. The researchers plan to conduct clinical trials and continue refining the bacterial assay for application to other bacterial agents.