NCJ Number
219244
Journal
Journal of Forensic Sciences Volume: 52 Issue: 4 Dated: July 2007 Pages: 800-805
Date Published
July 2007
Length
6 pages
Annotation
This paper reports on the development of a method for chemically induced enhancement of cell elution and recovery from cotton swabs that contain both perpetrator and victim DNA from vaginal swabs for rape kit analysis.
Abstract
The results show that the detergent-mediated elution of cells provided twofold enhancement of sperm cell recovery over conventional differential extraction (DE). The use of this method also recovered intact epithelial cells, which could be compatible with both conventional and novel DE processing. The improvement in sperm cell recoveries by using SDS (sodium dodecyl sulfate) in the elution buffer is ideal for increasing the efficiency of obtaining accurate DNA profiles from samples that contain low numbers of sperm cells. The choice of detergent affected sperm-cell yield, with anionic detergents having the greatest effect. The storage time of samples affected the concentration of detergent required for optimal sperm-cell recovery, with longer times requiring increased detergent concentrations. In order to mimic the vaginal epithelial cells collected on casework sample swabs, buccal epithelial cells were collected onto sterile cotton swabs and allowed to dry for a minimum of 3 days at room temperature. Swabs were then cut into pieces of consistent mass, and a 0.40 ml aliquot of semen was applied to each sample. Samples were dried and then stored at room temperature for specified amounts of time. All buccal swabs, vaginal swabs, and semen samples were obtained by voluntary donation from healthy females and males. Detergent solutions were prepared at the appropriate concentrations in Nanopure water using SDS. Sperm and epithelial cells eluted from each sample were visualized using light microscopy and counted using a hemacytometer. 7 figures and 20 references