DNA typing in thirty seconds with a microfabricated device

Abstract

We report the development of a practical ultrafast allelic profiling assay for the analysis of short tandem repeats (STRs) by using a highly optimized microfluidic electrophoresis device. We have achieved baseline-resolved electrophoretic separations of single-locus STR samples in 30 sec. Analyses of PCR samples containing the four loci CSF1PO, TPOX, THO1, and vWA (abbreviated as CTTv) were performed in less than 2 min. This constitutes a 10- to 100-fold improvement in speed relative to capillary or slab gel systems. The separation device consists of a microfabricated channel 45 micron x 100 micron in cross section and 26 mm in length, filled with a replaceable polyacrylamide matrix operated under denaturing conditions at 50 degrees C. A fluorescently labeled STR ladder was used as an internal standard for allele identification. Samples were prepared by standard procedures and only 4 microl was required for each analysis. The device is capable of repetitive operation and is suitable for automated high-speed and high-throughput applications.