What if the needle and syringe used to take a blood draw could also process and analyze the sample, and (with the help of a fluorescence detection system) display the test result? An international group of researchers believe they can make the self-contained “lab in a needle” a reality with the help of microfluidics technology. “We used the concept of lab on a chip, which compresses the entire function of a laboratory diagnostic test onto a tiny microfluidics chip, to create lab in a needle,” says Stephen Wong, chair of Systems Medicine and Bioengineering at Houston Methodist Research Institute, Texas, US, and co-author of the associated paper (1). “Our goal is to integrate sample acquisition and preparation into one device, a significant challenge that has slowed the development of point-of-care testing,” he added.
The prototype device is the first of its kind to integrate all the steps needed to process a sample for hepatotoxicity testing. Made up of two modules (see Figure 1), the system contains a chip which prepares the sample by performing tissue lysis and purifying mRNA. The second chip performs quantitative reverse transcriptase PCR in order to carry out gene expression analysis for two biomarkers associated with liver toxicity; alanine transaminase (ALT) and aspartate transaminase (AST). In an initial study of the device, liver samples of mice which had been dosed with the alkylating agent cyclophosphamide were analyzed. The researchers found that increased dosage with the drug could be correlated with increased expression of ALT and AST, which could be detected by their prototype. The device is not yet fully self-contained, and currently requires external instrumentation, but the team plans to create a smaller, more integrated version that could be used to test liver function in outpatients, in patients’ homes, or even in the field.
It goes without saying that an accurate point-of-care hepatotoxicity test could be incredibly beneficial, in particular given that current tests for liver function can take days to return a result, while the prototype “lab in a needle” could theoretically do it in just 30 minutes. The technology could also be applied to a range of lab tests, shortening the time it takes to get results and potentially bringing traditional lab tests to underserved areas, says Wong. He acknowledges that this is a disruptive technology, admitting that, “We actually move all the people-processing steps into the box, and automate them.” Further research with the prototype is ongoing, and if successful – as with most point-of-care devices – the assumption is that it would be complementary, rather than a replacement, to standard lab testing.
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References
- GS Lim, et al., “A lab-on-a-chip system integrating tissue sample preparation and multiplex RT-qPCR for gene expression analysis in point-of-care hepatotoxicity assessment”, Lab Chip, 15, 4032–4043, (2015). PMID: 26329655.
