Abstract:
The detection of saliva is important in forensic investigations as it can be a possible source for DNA testing when found. Current commercial forensic test-kits such as Phadebas® paper and tablets; and RSID™-Saliva are routinely used to detect saliva, however these are non-specific tests as they use α-amylase as their method of saliva detection, an enzyme found in many body fluids. There is a need for a more specific test and thus this research project focuses on the development of an immunological test-strip using HTN3. HTN3 reportedly has high specificity with saliva. There is also a need for further validation with the previous test-kits mentioned in terms of simulated storage conditions. Saliva was the primary body fluid investigated but seminal and vaginal fluid were also investigated both individually, as well as in mixtures with saliva. Stains were prepared and stored in either a controlled temperature freezer, refrigerator or left at room temperature in a controlled environment. Results from these experiments indicate non-significance between room temperature and chilled or frozen samples. This suggests that these test-kits can be used on chilled or frozen samples and still return positive results. Results from these experiments also indicate that positive results can be seen across all commercial test-kits at 1 month if left in storage at room temperature. Further experimentation involving a large sample population pool as well as testing long-term storage with temperature studies should be considered. Neat saliva stains only was tested with the HTN3 test-strip. Although initial results from this study were negative, possibly due to enzyme instability and / or problems with the colloidal gold conjugation; with further optimisation and experimentation work the test-strip can become a validated and accepted test within the forensic community.
