P044 – Rapid Direct STR Profiling from Toothbrushes Using microFLOQ® Direct Swabs: A DVI-Oriented Workflow Study

11:01

Wednesday August 19^th

Station 09

Duration: 12 minutes

03. Human identification

Salem Alketbi

Toothbrushes are frequently utilized as personal reference items in forensic investigations and disaster victim identification (DVI) due to their high potential for retaining epithelial cells and saliva-derived DNA. However, conventional DNA profiling workflows involving extraction and quantification are time-consuming, resource-intensive, and may result in DNA loss, particularly when dealing with limited or degraded samples. Direct amplification using microFLOQ® Direct swabs provides a rapid alternative by eliminating extraction and quantification steps, thereby reducing processing time, minimizing handling, and lowering the risk of contamination.

This study investigates the feasibility of direct STR profiling from toothbrushes using microFLOQ® Direct swabs within a DVI-oriented operational framework. A total of 30 donors provided toothbrush samples under standardized usage conditions. For direct amplification, three distinct sampling zones were evaluated to assess spatial variation in DNA recovery: bristle tips, mid-bristle regions, and base/head areas (n = 10 per group). A parallel conventional extraction workflow was performed for comparison. Samples were amplified using a standard STR multiplex system, and resulting profiles were assessed based on profile completeness, RFU signal intensity, peak balance, artifact occurrence (including split and shoulder peaks), and mixture detection.

It is anticipated that direct amplification will produce interpretable STR profiles from toothbrush samples within significantly reduced timeframes, supporting a rapid “toothbrush-to-profile” workflow within a few hours under optimized laboratory conditions. Variations in DNA yield and profile quality across sampling zones are expected, reflecting differences in biological material accumulation and retention within toothbrush structures. Additionally, while increased artifact presence may be observed in high-template regions, the overall profile quality is expected to remain suitable for reference purposes in DVI contexts.

The findings of this study support the development of a rapid, cost-effective DNA profiling workflow for DVI applications, where toothbrush-derived reference samples can be processed efficiently using direct amplification. This work further contributes to establishing practical sampling guidelines and operational strategies for the integration of direct amplification technologies into forensic identification pipelines.

Authors

Salem K. Alketbi (The Biology and DNA Section, General Department of Forensic Science and Criminology, Dubai Police, United Arab Emirates)
Shahad A. Muhammad (School of Law and Policing, University of Lancashire, United Kingdom)

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P044 – Rapid Direct STR Profiling from Toothbrushes Using microFLOQ® Direct Swabs: A DVI-Oriented Workflow Study

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