Capillary electrophoretic microdevice for highly sensitive short tandem repeat genotyping

Lab-on-a-chip (LOC) or microfabrication technology has paved its way in a variety of chemical and biological applications as a miniaturized analytical tool due to the benefits such as small sample consumption, high throughput synthesis and screening capability, fast analysis time and portability. Recently, the forensic human identification based on short tandem repeat (STR) genotyping has been performed on a microdevice platform, and the superior performance has been demonstrated. In this chapter, we focus on the capillary electrophoretic microdevice for highly sensitive and high-throughput STR genotyping which plays an important role in forensic investigations, particularly for sexual assault cases, paternity test, missing person identification, and evolutionary studies. To improve the sensitivity of STR genotyping analysis on a microdevice, we adopt the energy transfer fluorescent dye labels to increase the laser induced fluorescence (LIF) signal of multiplex STR PCR products, and a mini Y STR system to enhance PCR efficiency and success rate for degraded DNA by reducing the PCR amplicon size. In addition, the sample-stacking step during capillary electrophoresis (CE) concentrates the PCR products in a defined region of a microchannel, resulting in the enhanced STR peak intensities in the electropherogram. A 96-lane microfabricated capillary array electrophoresis (μCAE) system can perform the 96 sample STR typing in a high-throughput manner in less than 20 min with a single-base resolution. These advanced microtechnologies will accelerate the forensic STR typing process in a more sensitive, high-speed, and cost-effective way.