Miniaturized PCR chips for nucleic acid amplification and analysis: latest advances and future trends

Zhang, Chunsun; Xing, Da

It is essential to know the flow state of the micro fluids in the PCR chip since results depend on the fluid distribution and variation in the reaction system. Less attention has been devoted to the fluid mechanics of micro PCR devices than to other aspects. One notable advance has been to use semi-invasive fluid measurement techniques to measure flow fields inside a continuous-flow PCR chip. Curtin et al. used the micro particle image velocimetry (m-PIV) and pressure measurements to study the effect of PCR on biofluid viscosity in continuous-flow PCR chips (58) . It is reported that for low molecular weight substances, the biofluid viscosity will not increase after PCR. Li et al. used m-PIV to measure the velocity fields inside the continuous-flow PCR microchannel at various downstream locations (30) . Using m-PIV in the PCR chips represents a novel application of existing measurement techniques. For this technique, the size choice of the fluorescence seed particle is essential, as a particle that is too large or too small will cause undesirable effects on flow field.