Triaging of hair samples using fluorescent in situ detection

DiamondTM Nucleic Acid Dye (DD) has been evaluated for visualizing DNA material on various evidence types, including nuclei in plucked hair roots. While plucked hair roots exhibit a rapid DNA visualization process, shed hairs, even when stained with DD, pose challenges due to the lack of cell nuclei. In the absence of clear cell nuclei, the sole indicator of DNA presence is the fluorescent signal from DD bound to DNA. This study aimed to assess the stability of the fluorescent signal in shed hairs, revealing a rapid decline within 2-3 min post-staining, likely attributed to the cell-free nature of the DNA present on the hair root. Consequently, immediate microscopic visualization and imaging post-staining are crucial during shed hair examination.