Plastic biochannel hybridization devices: a new concept for microfluidic DNA arrays

Conventional DNA hybridization assay kinetics depends solely on the diffusion of target to surface-bound probes, causing long hybridization times. In this study, we examined the possibilities of accelerating the hybridization process by using microfluidic channels ("biochannels") made of polycarbonate, optionally with an integrated pump. We produced two different devices to study these effects: first, hybridization kinetics was investigated by using an eSensor electrochemical DNA detection platform allowing kinetic measurements in homogenous solution. We fabricated an integrated cartridge for the chip comprising the channel network and a micropump for the oscillation of the hybridization mixture to further overcome diffusion limitations. As a model assay, we used an assay for the detection of single-nucleotide polymorphisms in the HFE-H gene. Second, based on the biochannel approach, we constructed a plastic microfluidic chip with a network of channels for optical detection of fluorescent-labeled targets. An assay for the simultaneous detection of four pathogenic bacteria surrogate strains from multiple samples was developed for this device. We observed high initial hybridization velocities and a fast attainment of equilibrium for the biochannel with integrated pump. Experimental results were compared with predictions generated by computer simulations.