A low-cost mobile device has been engineered that combines cell phone and satellite communication technologies with fluid miniaturization techniques and performs all essential enzyme-linked immunosorbent assay (ELISA) functions.

The device combined the portability of mobile technology with the detection potential of enzyme-linked antibodies to create a fully automated and portable microfluidic device dubbed the “mChip,” and has been tested in an African setting.

A team of scientists including those at Columbia University (New York, NY, USA) who invented the device assessed its ability to perform serodiagnostic testing for human immunodeficiency virus (HIV) in a field setting and synchronize the results in real time with electronic health records. They tested serum, plasma, and whole blood samples collected in Rwanda and on a commercially available sample panel made of mixed antibody titers.

The handheld apparatus, which is a mobile microfluidic chip for immunoassay on protein markers (mChip) device, captures the essential functions of ELISA as performed by pipetting robots, microplate readers, desktop computers, and communication hardware. The device does not need grid-based power and is sufficiently low in cost and energy consumption to be suitable for resource-limited settings. ELISA is the most sensitive and commonly used laboratory diagnostic for HIV, and historically has taken hours and sometimes days to provide a result. The mChip device, however, produces a result in just 15 minutes.

To explore the performance of the mChip device on coinfected samples, the team evaluated the HIV accuracy of the mChip device on 167 Rwandan patient samples. Also, 100 plasma samples from Rwandan patients were tested for hepatitis B and C (HBV and HCV), as well as 67 serum samples from patients who were also tested for syphilis and herpes simplex virus (HSV-2). Despite the high prevalence of viral hepatitis, 99 positive for HBV and/or HCV in the sample set and the substantial number of sexually transmitted infections, 31 positive for syphilis and/or HSV-2, the diagnostic sensitivity of the mChip device was high at 100%, as was the diagnostic specificity at 99%, with only two false positives.

Samuel K. Sia, PhD., a bioengineer and the senior author of the study, referring to the data repository that doctors can access, said, "Now, with a single push of a button, there is automation not only from the sample to the result, but to the synchronization of data to the cloud. This automation is very important because it minimizes user error and user variability. The real power is that one finger prick can give you multiple rapid test results, making it cheaper and more convenient.” The cost of the device is estimated at USD 100. The study was published on January 17, 2013, in the journal Clinical Chemistry.

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