In this study, a novel microfluidic device with microbead array was developed and sensitive genotyping of HBV was demonstrated using quantum dot as labels. This device was assembled by using two PDMS slabs featured with different microstructures and channel depths for the construction of a functional region comprising a chamber array and a single sampling microchannel. Since the chamber array and its sampling channel are of different channel depths and are bonded face-to-face, weir structures are generated to confine the microbeads which could be addressed using the microfluidic channel. Highly sensitive virus DNA detection was achieved by the enhanced mass transport in the microfluidics and the rapid reaction dynamics of suspension microbead array. The device could detect 1000 copies/mL of HBV virus in clinical serum samples using in vitro transcribed RNA as the target molecules. Based on DNA hybridization with quantum dots labels, on-chip virus genotyping was also demonstrated with high discrimination specificity and sensitivity (4 pM, S/N >3) using synthesized HBV DNA probes. This microfluidic device combines the rapid binding kinetics of homogeneous assays of microbead array, the liquid handling capability of microfluidics, and the fluorescence detection sensitivity of quantum dots to provide a platform for high sensitivity virus DNA analysis with small reagent consumption, short assay time and parallel detection.
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