U.S. flag

An official website of the United States government, Department of Justice.

Microchip Analyzer for Forensic Short Tandem Repeat Typing of Single Cells

NCJ Number
Tao Geng; Richard A. Mathies
Date Published
June 2013
39 pages
This report describes a novel single-cell short tandem repeat (STR) typing method with high sensitivity, fidelity, and throughput that combines microfluidic droplet generation with single-cell multiplex emulsion PCR.
This project developed an agarose microfluidic droplet method in order to separately type single cells in a highly parallel manner. The unique thermo-responsive sol-gel switching property of agarose enables the gel droplets containing the individual cells to be flexibly processed for cell lysis, amplification, mechanical manipulation, and long-term storage. Following lysis and digestion of the cell-containing droplets in a chemical lysis buffer containing sodium dodecyl sulfide and proteinase K, genome DNA is released from the cell but remains trapped in the porous agarose network. The expected profiles of nine STR loci could be successfully detected from pure and mixed single cells (GM09947 and GM09948 human lymphoid cells) with high single-genome integrity. Improved sensitivity, resolution, reliability, robustness, and speed of single-cell STR typing will produce more accurate and faster results at crime laboratories in cases of evidence samples that contain low amounts of cells or mixed cells. The researchers involved in this project envision that this novel technology will be applicable in analyzing real-world samples in the casework that involves low-abundance evidence materials and multiple suspects. It should also facilitate new novel uses of "touch evidence." 10 figures, 2 tables, and 28 references

Date Published: June 1, 2013