DOI: https://doi.org/10.55373/mjchem.v24i2.199

Keywords: Fabrics; DNA; abandoned building; jungle; construction site; environmental exposure

Abstract

Bloodstains are one of the most common pieces of biological evidence found at the scene of a violent crime. Bloodstains found at a crime scene usually occur on items of clothing. Thus, blood on fabric needs to be understood. This research was conducted to identify the types of fabrics that retain a higher concentration of DNA and the persistence of this DNA when exposed to different environmental conditions such as sunlight, high humidity and heavy rain. Three different locations were used in this study to mimic real crime scenes, namely a jungle, an abandoned building and a construction site. Ten different types of fabrics used for this study were satin, chiffon, linen, polyester, cotton, crepe, argenti, valentro, lycra and georgette. The fabric samples were stained with fresh human blood and exposed to different environmental conditions for seven days. Samples were collected every 24 hours. DNA extraction was done using a NEXprepTM NexK-3100 Genomic Mini Kit. The concentration of DNA was measured using BioPhotometer Plus by Eppendorf. The type of fabric that retained the highest concentration of DNA when exposed under three different environmental conditions was crepe. The concentration of DNA retained by the fabric samples in an indoor abandoned building was higher compared to the concentration of DNA retained by the fabric samples in an outdoor jungle area and outdoor construction site. The amount of DNA recovered from these fabrics varied according to the different environmental conditions. The possibility for DNA contamination increased with time as the bloodstained fabrics were exposed to the uncontrolled environment. Therefore, the biological materials, substrates and effects of environmental exposure need to be properly understood and studied by forensic scientists so that the results of such analyses may be correctly determined and interpreted.