Work

The use of non-thermal plasma for DNA decontamination in a forensic vacuum metal deposition chamber: A proof of concept study

Year: 2025

Type: article

Abstract: Vacuum Metal Deposition (VMD) is routinely deployed for fingermark development on various types of evidence. In efforts to implement a sequential forensic workflow where fingermarks are processed before DNA collection to maximise evidential value, it is essential to prevent cross-contamination between analysed items. Non-thermal plasma (NTP) presents a potential advantage in DNA decontamination as it can reach areas that are inaccessible to conventional UV-C light and eliminates the need for solvents that might interfere with the vacuum-based systems. In this study, different NTP conditions generated within a VMD chamber were tested on human cells with known DNA concentrations, and cell-free DNA. This included variations in power (maximum and medium), exposure times (0.5 h, 1 h, 2 h), and pressures (1.68, 2, 4.27 ×10 −1 mbar). Overall, a reduction of approximately 100-fold in DNA concentration was observed after plasma treatment. Out of the tested conditions 1 h, 2 × 10 −1 mbar and maximum power proved to be the most stable plasma for the DNA removal. While UV-C light was more efficient at degrading cell-free DNA in direct line of sight by reducing DNA levels below the limit of detection and showing significant degradation, NTP was more effective at eliminating DNA out of the line of sight. These findings suggest that NTP could be a promising tool for DNA decontamination of forensic instruments like VMD. Future research should focus on optimizing NTP settings, including power output and vacuum conditions, to ensure complete DNA removal. • Non-thermal plasma (NTP) may be generated within a forensic Vacuum Metal Deposition (VMD) chamber. • The liberated species within NTP are damaging to forensic DNA sources. • At least 100-fold reduction in DNA quantities are obtained through NTP exposure. • NTP may be retrospectively integrated into VMD. • NTP has benefits over chemical and/or UVC decontamination methods.

Source: Forensic Science International

DOI: 10.1016/j.forsciint.2025.112453

Authors: Katie Hussain, Roberto S.P. King, Raymond N. Allan, Kevin Farrugia, Urszula Krzeminska-Ahmadzai

Institution: De Montfort University

Language: English

Topic: Forensic Fingerprint Detection Methods

Subfield: Safety Research

Field: Social Sciences

Domain: Social Sciences

SDG: Peace, justice, and strong institutions

Open Access status: hybrid

Estimated APC paid: $4,580