Development of a novel latent deoxyribonucleic acid detection technique for crime scene investigation using quartz tuning fork-based biosensor technology.

The forensic Deoxyribonucleic Acid (DNA) fingerprinting is a tool for investigating crime scenes by identifying/tracing criminals and linking crime scenes. However, in cases where experts are unable to detect and identify any biological traces or human-derived cells at the crime scene or while testing the samples in the laboratories, all the advantages offered by forensic laboratories lose their significance. It becomes a waste of time, effort, and resources allocated to these laboratories. Therefore, there is an urgent need for technology that enables crime scene experts to detect latent and concealed human traces before they leave the scene. This work aims to provide a novel qualitative and quantitative approach to tackle the challenges faced by crime scene experts in identifying challenging traces using instant, low-cost, uncomplicated, portable, sensitive detection technology by introducing the Quartz Tuning Fork (QTF)-based biosensor technology as an initial screening technique. A probe layer functionalized the QTF-based biosensor to capture DNA fragments. The response of the functionalized QTF sensor to different concentrations of DNA was measured as a resonance frequency shift, which increased as the concentration of DNA increased. The QTF response for DNA was also confirmed by measuring the resonance frequency of the functionalized QTF after capturing DNA and after washing with DNA removal solution (DNAZap). The resonance frequency of the QTF immersed in DNA was increased after immersion in the DNA removal solution. Finally, functionalized QTF showed a high sensitivity for the DNA fragments with a limit of detection of 140 pg/µl.