‘Lab-on-a-stick’ offers fast detection of antibiotic resistance
Academics at Loughborough University and the University of Reading in the UK have developed a portable, power-free test for the rapid detection of bacterial resistance to antibiotics.
The new test called Lab-on-a-Stick is an inexpensive microfluidic strip, that consists of tiny test tubes about the size of a human hair, capable of identifying bacteria found in urine samples and checking if they are resistant to common antibiotics.
Lab-on-a-Stick is a ‘dip and read’ method using a transparent microcapillary film suitable for naked eye detection or measurement with portable, inexpensive equipment such as a smartphone camera. This makes it easy to use, cheap to manufacture, and at least 12 times faster than current microbiological tests.
It is the result of research by Dr. Nuno Reis, Lecturer in Chemical Engineering at Loughborough University, and Dr. Al Edwards, Associate Professor in Biomedical Technology at the University of Reading. The full study has been published in the Lab on a Chip journal.
The study showed that dipstick tests routinely used for testing in a variety of scenarios from soil pH strips for the garden to pregnancy tests, could be updated using the latest approach in miniaturized testing technology to help form the basis of a new generation of advanced, yet affordable, point-of-care tests for global diagnostics.
As part of the study, different cellular tests were carried out to demonstrate the full potential of Lab-on-a-Stick devices for a range of clinical situations:
Anti-microbial resistance – this was measured with E. coli samples typical of common urinary tract infection (UTIs). UTIs can be hard to treat with antibiotics because antibiotic resistance is so common and lab testing takes at least two days. The assay detects antibiotic resistance. This demonstrated the advantage of using the microcapillary film which enables 10 different concentrations of antibiotic per sample to be tested with a single test strip. The research team are currently optimising this so that the test, which currently requires overnight incubation in a multi-well plate, could be completed in less than two hours in a single test strip in the future.
Bacteria identification – classical analytical microbiology tests used for the identification of bacteria were miniaturized and performed in parallel microcapillaries, resulting in simple and rapid identification of bacteria. To identify bacteria, many different tests must be performed on every sample, illustrating again the benefits of microcapillary film which performs 10 tests per test strip. This study demonstrated a four-hour test to distinguish two very closely related bacteria – a harmless laboratory strain of E. coli from a type of Salmonella that causes food poisoning.
ABO blood typing – a simple blood test that takes only two minutes was miniaturized and the results were recorded using an everyday digital camera.
Dr. Reis said: “This is a major step towards miniaturizing complex, routine microbiological and clinical tests that cannot at the moment be performed outside of the laboratory setting.
Dr. Edwards, co-author of the study, said: “This is the latest demonstration of our exciting new technology called microcapillary film. Many researchers across the world have shown how miniaturizing lab tests can speed them up using microfluidic Lab-on-a-Chip devices. But these are too expensive to be useful outside the laboratory. What we have done is to develop a low cost way of making thousands of miniature test tubes, so that we can use them for many important applications. Lab-on-a-Stick shows yet again how versatile these microscopic test tubes are.”
