Follow us
P243 – Advanced Rapid Identification of Vaginal Fluid with Nucleic Acid based LFA Technology
The accurate identification of body fluids recovered from crime scenes is a cornerstone of forensic investigation, providing crucial context and evidence. While rapid immunochromatographic lateral flow tests are commercially available for fluids such as blood, semen, and saliva, a reliable and rapid test for human vaginal fluid has remained elusive. This gap is primarily due to the lack of a unique, stable protein marker that can serve as a specific antigen target. Current methodologies for vaginal fluid identification, including histological staining and microbiome analysis, suffer from limitations such as cross-reactivity with other cell types, lack of universal markers, and extended processing times.
To address this critical need, we present a proof-of-concept for a novel Nucleic Acid Lateral Flow Assay (NALFA) that utilizes molecular beacon technology for the rapid, sensitive, and specific identification of human vaginal fluid. This approach shifts the detection target from proteins to unique nucleic acid sequences. We have designed molecular beacons, hairpin-shaped oligonucleotide probes, that are specific to miRNA markers known to be present in human vaginal fluid. These beacons enable a colorimetric readout on a lateral flow strip upon hybridization with their target sequence.
Our results demonstrate that the NALFA can successfully discriminate vaginal fluid from other forensically relevant biological matrices, including blood, semen, and saliva, with no observed cross-reactivity. The assay is highly sensitive, achieving a limit of detection of 1 pmol of target nucleic acid. A key advantage of this protein-free system is its enhanced thermal stability; functional tests confirmed the assay's robust performance at temperatures up to 70°C, which is a significant improvement over traditional antibody-based tests and facilitates transportation and storage in varied environmental conditions. Furthermore, the integration of channelled membrane technology, provides a pathway for miniaturized multiplex analysis, allowing for the simultaneous detection of multiple confirmatory markers within a single device.
In summary, this molecular beacon-based NALFA offers a rapid, cost-effective, and highly stable solution for the definitive identification of human vaginal fluid. By leveraging specific miRNA markers, it overcomes the limitations of existing serological and molecular methods, significantly reducing the risk of false positives and providing forensic practitioners with a powerful new tool for evidential analysis. Future work will focus on validating the assay with a larger cohort of forensic samples and integrating it into a fully multiplexed format.
Author
- Nidhi Subhashini (SERATEC GmbH, Germany)
On the same topic
