Chemical biology news from across RSC Publishing.
Faster superbug detection
07 July 2008
Chip technology could cut the wait for test results on clinical samples, say US scientists. A team at the University of Chicago has developed a method to detect bacteria in blood plasma samples and simultaneously screen their response to antibiotics.
Converting a weak bacterial solution into droplets means it can be screened against several different antibiotic
The group's technique works by mixing a sample with a dye that fluoresces in the presence of bacteria; the mixture is then converted into droplets inside a microfluidic chip. If the sample contains bacteria some of the droplets will contain a single bacterium and fluoresce. Because of the very small droplet size, the occupied droplets will have a high bacterial density, removing the need to incubate samples to increase their concentration before detection.
Rustem Ismagilov, who led the team, explains that his motivation was rooted in improving medical diagnostic tests. Traditional methods of diagnosing bacterial infections rely on time-consuming sample incubations or amplifying the bacterial DNA which, while faster, cannot be used to look at antibiotic response. 'Our technique can potentially provide access to new types of diagnostic tests for bacterial infections and simultaneously identify a treatment regime to provide same-day test results,' says Ismagilov.
Samuel Sia, an expert in lab-on-a-chip diagnostic devices at Columbia University, New York, US, is enthusiastic about the research. 'The finding that confining a single bacterium to a small volume can decrease detection time is a striking demonstration of the advantages of microfluidics,' he says. Whilst he explains that considerable development and clinical testing will be needed before such an assay could be used for real-world diagnostics, he adds that 'the experimental design is very clever, and the results convincing.'
Link to journal article
Detecting bacteria and determining their susceptibility to antibiotics by stochastic confinement in nanoliter droplets using plug-based microfluidics
James Q. Boedicker, Liang Li, Timothy R. Kline and Rustem F. Ismagilov, Lab Chip, 2008, 8, 1265
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