Microfluidic device for rapid (< 15 min) automated microarray hybridization

Background: Current hybridization protocols on microarrays are slow and need skilled personnel. Microfluidics is an emerging science that enables the processing of minute volumes of liquids to perform chemical, biochemical, or enzymatic analyzes. The merging of microfluidics and microarray technologies constitutes an elegant solution that will automate and speed up microarray hybridization. Methods: We developed a microfluidic flow cell consisting of a network of chambers and channels molded into a polydimethylsiloxane substrate. The substrate was aligned and reversibly bound to the microarray printed on a standard glass slide to form a functional microfluidic unit. The microfluidic units were placed on an engraved, disc-shaped support fixed on a rotational device. Centrifugal forces drove the sample and buffers directly onto the microarray surface. Results: This microfluidic system increased the hybridization signal by similar to 10fold compared with a passive system that made use of 10 times more sample. By means of a 15-min automated hybridization process, performed at room temperature, we demonstrated the discrimination of 4 clinically relevant Staphylococcus species that differ by as little as a single-nucleotide polymorphism. This process included hybridization, washing, rinsing, and drying steps and did not require any purification of target nucleic acids. This platform was sensitive enough to detect 10 PCR-amplified bacterial genomes. Conclusion: This removable microfluidic system for performing microarray hybridization on glass slides is promising for molecular diagnostics and gene profiling. (c) 2005 American Association for Clinical Chemistry.