The Utility of Polyester and Cotton as Swabbing Substrates for the Removal of Cellular Material from Surfaces*

Abstract

Various types of cotton and polyester fabrics were tested to ascertain the optimal physical and chemical characteristics of fabrics needed for the removal of cellular material from surfaces. DNA quantitation values obtained on dried saliva stains showed no difference between cotton and polyester across all constructions and solvent conditions. Fabrics used dry and with water yielded higher quantitation values than those used with isopropanol. Quantitation values were also higher for wovens and nonwovens than knits across all solvent conditions. Low thread count fabrics used with water yielded higher quantitation values, but no correlation between thread count and quantitation values was observed with dry fabrics. A low thread count woven fabric, however, outperformed other tested fabrics when swabbing object surfaces in a highly used room. Full DNA profiles from fingerprints on glass surfaces were obtained with low thread count woven and nonwoven fabrics but not with the knit fabric tested.

Swabs as DNA Collection Devices for Sampling Different Biological Materials from Different Substrates

“…One possible explanation for this discrepancy is that woven fabric swatches as used by Mulligan et al. may not be directly comparable to wound swabs due to the differences in the structure of their fibers.…”

“…This demonstrates that the effect of extraction efficiency, whilst potentially affecting overall swabbing efficacy, may have been outweighed by high collection efficiency. Previous comparison of the DNA collecting capacity of polyester and cotton fabric swatches showed that, whilst there was no significant difference between the DNA quantities collected by cotton and polyester as a whole, the amount of DNA collected was inversely proportional to the density of the fibers in the fabric. This finding does not concur with the results of this study, which ranks the FABSwab higher for DNA collection efficiency than other cotton swabs, which appear, by both weight (Table ) and observation, to be less densely wound.…”

The Extraction and Recovery Efficiency of Pure DNA for Different Types of Swabs

“…For forensic (human biological) applications cotton , foam , nylon flocked , polyester , and rayon (viscose) swabs have been tested with epithelial , saliva and vaginal samples and have been expressed in terms of the number of alleles present in the DNA‐profile (), the DNA quantity/yield (ng), the concentration (ng/μL) or percentage . The various swabs have been ranked by Verdon et al according to their combined collection and extraction efficiency.…”

“…The various swabs have been ranked by Verdon et al according to their combined collection and extraction efficiency. Typical extraction volumes for forensic applications have been in the order of microliters . Only a few experiments have been performed to determine the extraction efficiency, whereas a swab may have high collection properties, but bad performance upon release of the sample .…”

Modified Practical Approach in Repeated DNA Studies of Biological Evidence of Sexual Assault

“…the widely used techniques for collecting DnA traces by taking smears with cotton or nylon fabric swabs, as well as by cutting out of small sections of materials which carry organic traces, are classical (27) and there is still no well-established competitive alternative. cotton swabs are routinely used in the practice of examining women who have been a victim of sexual assault, and vaginal and/or anal smears are necessarily taken (21).…”