As well as a smartphone camera, the test, which could be adapted to detect a variety of bacterial infections, takes advantage of widely available reagents and new micro-engineered materials. Researchers say the simplicity of the test, which has now passed the proof-of-concept stage, could deliver a new way to quickly identify treatments for patients in poorer or remote regions.
Described in the journal Biosensors and Bioelectronics, the test uses antibodies to capture bacterial cells in very thin capillaries within a plastic strip, detecting and identifying the cells optically rather than through the microbiological methods currently used.
Dr Nuno Reis, from Bath's Department of Chemical Engineering, led the development of the test. He says: "The test is small and portable - so it has major potential for use in primary care settings and in developing countries. Currently, bacterial infections in UTIs are confirmed via microbiological testing of a urine sample. That is accurate, but time-consuming, taking several days. We hope that giving medical professionals the ability to quickly rule in or rule out certain conditions will allow them to treat patients more quickly and help them make better decisions about the prescription of antibiotics."
The test is carried out by passing a urine sample over a ridged plastic micro-capillary strip, containing an immobilizing antibody able to recognize E. coli bacterial cells. If E. coli is present in the sample, antibodies in the reagents will bind with it, stopping it from passing through the section of plastic strip. Finally, an enzyme is added that causes a change in color that can be picked up by a smartphone camera.
The system also measures the concentration of E. coli in the sample by analyzing an image taken by the camera. The procedure is simple and could be manually operated or fully automated without any need for a mains power supply.
MEDICA-tradefair.com; Source: University of Bath
