All ETDs from UAB

Advisory Committee Chair

Jason Linville

Document Type


Date of Award


Degree Name by School

Master of Science in Forensic Science (MSFS) College of Arts and Sciences


Studies have shown that spermatozoa persist on cotton fabric under various conditions after being washed multiple times. The purpose of this study was to observe the number of sperm cells removed from cotton fabric over the course of multiple wash cycles. This study also explored how various treatment methods impact the rate of removal and number of cells removed. In this study, sperm cells were counted using a hemacytometer to estimate the average number of cells in a 20 µL semen stain. Twenty stains were prepared on cotton fabric and washed in a microfuge tube with 200 µL of reverse osmosis (RO) water. The cells removed were counted using a hemacytometer. Four stains were washed without a spin basket, and four stains were washed with a spin basket until cells were no longer removed. For samples washed with a spin basket there was an exponential decrease between the first and second wash cycle, and after 5 washes the number of cells removed was less than 1% of the cells in the stains. Twelve additional stains were washed with a spin basket for 5 washes, and the cells removed in each wash were counted. Under normal washing conditions it was determined that between 40-60% of cells were removed after 5 washes, but by the 5th wash the number of cells removed was less than 1%, indicating that subsequent washes would have little to no effect. Despite this, a full genetic profile was detected from each of the washed stains through DNA analysis. Three fabrics were washed using variable conditions—teasing the fabric, boiling water, and a cellulase solution. The cells in each wash were counted using the same hemacytometer method. Of the variable treatments, teasing the fabric showed the greatest impact in removing additional cells. Alternatively, the boiling water and cellulase treatments seemed to have no effect, and the trendlines were consistent with the exponential decrease seen in the other washed stains in the study. A full genetic profile was detected from each of the washed stains regardless of the washing condition or the estimated number of cells removed.



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