Presenter Information

Lindsey Campany, B.A., Forensic Science and Law Program, Duquesne University

Abstract

With advancements in the DNA technology and methodology, more complete DNA profiles can be obtained. Extraction procedures and their reagents have been optimized for maximal DNA yield, but the cotton swab used and provided for sexual assault examinations has not advanced. Despite research suggesting the cotton swab’s absorbent nature and its inclination to retain cellular material, the field of forensic nursing has not yet implemented another swab.

Three swabs that this research will be evaluating are nylon flocked swabs, cotton swabs, and the cytobrush swab. The nylon flocked and cotton swabs have been studied for their efficiency, but no studies have evaluated the cytobrush for forensic evidence collection.

Sample preparation consisted of individually submerging three different swabs in microcentrifuge tubes containing 50 µL of a 1:250 seminal fluid dilution. These mock sexual assault samples were carried through DNA processing methods to analyze what swab yielded the highest sperm DNA concentration and best genetic profile. It was hypothesized that the nylon flocked and cytobrush swabs would be more efficient than the cotton swab for sperm recovery, and the cytobrush swab would be the most efficient for sperm recovery.

The results showed that the nylon flocked and cytobrush swabs had five out of twelve samples with higher and significantly different DNA concentrations than the concentrations from the cotton swab. The results also suggest that the structure of the swab effects the overall efficiency for sperm elution. Also, the swab type did not have an effect on the quality of the electropherogram.

School

Bayer School of Natural and Environmental Sciences

Advisor

Pamela Marshall, Ph.D.

Submission Type

Poster

Included in

Biology Commons

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An Analysis of Extraction Efficiencies of Various Swabs on Sperm Recovery

With advancements in the DNA technology and methodology, more complete DNA profiles can be obtained. Extraction procedures and their reagents have been optimized for maximal DNA yield, but the cotton swab used and provided for sexual assault examinations has not advanced. Despite research suggesting the cotton swab’s absorbent nature and its inclination to retain cellular material, the field of forensic nursing has not yet implemented another swab.

Three swabs that this research will be evaluating are nylon flocked swabs, cotton swabs, and the cytobrush swab. The nylon flocked and cotton swabs have been studied for their efficiency, but no studies have evaluated the cytobrush for forensic evidence collection.

Sample preparation consisted of individually submerging three different swabs in microcentrifuge tubes containing 50 µL of a 1:250 seminal fluid dilution. These mock sexual assault samples were carried through DNA processing methods to analyze what swab yielded the highest sperm DNA concentration and best genetic profile. It was hypothesized that the nylon flocked and cytobrush swabs would be more efficient than the cotton swab for sperm recovery, and the cytobrush swab would be the most efficient for sperm recovery.

The results showed that the nylon flocked and cytobrush swabs had five out of twelve samples with higher and significantly different DNA concentrations than the concentrations from the cotton swab. The results also suggest that the structure of the swab effects the overall efficiency for sperm elution. Also, the swab type did not have an effect on the quality of the electropherogram.