Digital polymerase chain reaction (dPCR) circumventing the external calibration and potentially providing absolute quantification of nucleic acids has become an increasingly popular manifestation of PCR in biological researches. However, currently reported or commercial dPCR devices are not suitable for applications in laboratories or zones with limited infrastructures, due to low function integration, cost-inefficiency, or weak mobility. Herein, in order to enable accurate DNA quantitative analysis in such situations, we have developed a smartphone-based mobile dPCR device integrated with thermal cycling control, on-chip dPCR, data acquisition, and result analysis. All the function units are automatically controlled using a customized Android software. The device is approximately 90 mm × 90 mm × 100 mm in size and about 500 g in weight, only costing about 320 dollars except the smartphone. Coupled with the self-priming dPCR chip previously developed by our lab, the device is able to accurately quantify down to 10 copies of the human 18 S ribosomal DNA fragment inserted in a plasmid. Comparing to the commercial QuantStudio™ 3D dPCR platform, our device achieves a comparable analytical accuracy. Besides, our device is capable of detecting single molecule of cancer biomarker gene CD147 in a low number of HepG2 cells. Therefore, our dPCR device as a low-cost, potable, and robust tool for highly accurate DNA quantitative analysis has a great potential in Point-of-care (POC) applications.
Keywords: Cancer biomarker gene; Digital PCR; Microfluidic chip; Point-of-care; Resource-limited settings; Smartphone.
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