Sample stacking capillary electrophoretic microdevice for highly sensitive mini Y short tandem repeat genotyping.
Lab-on-a-chip provides an ideal platform for short tandem repeat (STR) genotyping due to its intrinsic low sample consumption, rapid analysis, and high-throughput capability. One of the challenges, however, in the forensic human identification on the microdevice is the detection sensitivity derived from the nanoliter volume sample handling. To overcome such a sensitivity issue, here we developed a sample stacking CE microdevice for mini Y STR genotyping. The mini Y STR includes redesigned primer sequences to generate smaller-sized PCR amplicons to enhance the PCR efficiency and the success rate for a low copy number and degraded DNA. The mini Y STR amplicons occupied in the 5- and 10-mm stacking microchannels are preconcentrated efficiently in a defined narrow region through the optimized sample stacking CE scheme, resulting in more than tenfold improved fluorescence peak intensities compared with that of a conventional cross-injection microcapillary electrophoresis method. Such signal enhancement allows us to successfully analyze the Y STR typing with only 25 pg of male genomic DNA, with high background of female genomic DNA, and with highly degraded male genomic DNA. The combination of the mini Y STR system with the novel sample stacking CE microdevice provides the highly sensitive Y STR typing on a chip, making it promising to perform high-performance on-site forensic human identification.
Chen
Yuchao
Y
Department of Chemical and Biomolecular Engineering (BK21 program) KAIST, 335 Gwahangno, Yuseong-Gu, Daejeon, Republic of Korea.
Choi
Jong Young
JY
Choi
Seok Jin
SJ
Seo
Tae Seok
TS
D004247:DNA / Q000737:chemistry*; D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D018598:Minisatellite Repeats / Q000235:genetics*; D025202:Molecular Diagnostic Techniques; D020411:Oligonucleotide Array Sequence Analysis; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods*; D013050:Spectrometry, Fluorescence
D004247:DNA