Forensic Detection: A Comprehensive Review of SERS Mechanisms and Applications

Forensic investigations increasingly demand analytical techniques that are rapid, highly sensitive, and nondestructive, while remaining reliable for complex, trace-level, and degraded evidence. Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful analytical platform that addresses these requirements by providing molecular fingerprinting with ultrahigh sensitivity and enabling single-molecule detection. This review critically examines recent progress in forensic SERS and highlights its expanding role across diverse forensic applications. Few examples are questioned in document analysis and ink discrimination, fingerprint imaging and chemical mapping, biological trace evidence, gunshot residue and explosive detection, and illicit drug identification in various complex matrices. Nanoengineered plasmonic architectures as advanced SERS substrates, ranging from silver and gold nanocubes, nanorods, nanopastes, and sol–gel capillaries to adhesive nanofilms and flexible “place-and-play” platforms, have shown signal enhancement and operational simplicity. This review also discusses current limitations and validation requirements and outlines technological pathways forward, including hybrid analytical systems, microfluidic and lab-on-a-chip SERS devices, AI-assisted spectral libraries, and sustainable, low-cost substrate designs. With these developments, SERS is increasingly deployable and transformative, positioning it as an analytical platform for routine implementation in next-generation forensic science.