Advances in Saliva Detection for Forensic Investigations: A Modern Perspective

Saliva, an abundant and easily obtainable biological fluid, has emerged as a crucial type of forensic evidence due to its widespread presence at crime scenes and its ability to provide both biochemical and genetic information. It has a crucial importance in the justice system, as It helps to identify perpetrators, clear the wrongly accused, and assist in criminal investigations. It give wide range of information in forensic contexts such as DNA and Genetic Information, Blood Group Typing, Microbial Signature, Lifestyle and Behavioral Clues etc. It can be transferred during numerous activities such as biting, licking, speaking, coughing, or kissing, thereby frequently appearing in cases of assault, sexual violence, and homicide. Traditionally, saliva identification relied heavily on enzymatic assays targeting alpha-amylase; however, these methods often lacked specificity and were prone to false positives. With the advancement of molecular biology, nanotechnology, and analytical instrumentation, a range of novel techniques has been developed to detect and confirm the presence of saliva with greater sensitivity and specificity. These include immunoassays, RNA and DNA profiling, spectroscopy-based techniques, biosensors, and epigenetic markers. This review highlights both conventional and cutting-edge approaches to saliva detection, discusses their forensic relevance, and evaluates their potential for integration into routine forensic workflows. The continuous innovation in saliva detection techniques not only enhances the evidentiary value of this biological fluid but also contributes significantly to the accuracy and reliability of forensic investigations.