Abstract
Forensic science depends on identifying biological fluid stains to maintain DNA for profiling and associating suspects with crime scenes. These stains can include urine and other secretions; however, presumptive and confirmatory tests often target specific fluids and might damage DNA because of destructive chemical processes. Traditional reagents like 4-dimethylaminocinnamaldehyde (DMAC) allow for quick screening but have low specificity and sensitivity in complex crime scene matrices. Hence, there is a necessity for a universal, highly sensitive, and non-destructive technique for the accurate analysis and differentiation of bodily fluids. In this study, we present an eco-friendly technique for synthesizing silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) utilizing extracts from the stems of Sclerocarya birrea and Moringa oleifera as reducing and stabilizing agents in aqueous medium. These nanoparticles were employed as alternative materials for urine analysis at the crime scene. Various characterization techniques, including Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and spectrophotometry, were used to analyse the nanoparticles. XRD results indicated a face-centred cubic crystalline structure, while microscopy observations showed that the nanoparticles were mainly spherical, with some in hexagonal and polyhedral shapes. Fluorescence spectroscopy revealed that AgNPs and AuNPs significantly improved the excitation and emission signals of DMAC in urine analysis when compared to plant extracts alone. Furthermore, electrophoresis gel and nanophotometer analysis showed enhanced DNA recovery and less degradation after nanoparticle-assisted urine testing. These results indicate that these nanoparticles function as non-toxic signal enhancers and protective agents, thereby enhancing sensitivity, specificity, and DNA preservation in forensic analysis.