Fluorescence spotting of latent sweat fingerprints with zinc oxide carbon dots embedded in a silica gel nanopowder: a green approach†
Abstract
The construction of low-cost fluorescent-labelled materials is needed to meet the current demand in forensic security perceptions, such as identifying latent fingerprints (LFs). Colossal works of literature are spotted in LFs with fluorescent nanomaterials since fluorescence is among the most efficient identification techniques. However, many challenges remain, including low selectivity, complex handling, nanoparticle toxicity, and high cost. This study demonstrates the biocompatible zinc oxide-carbon dots/silica gel (CZnO-dots/Si) nanopowder as a new fingerprint visualizing agent. It is low-cost and non-toxic since it is prepared using a natural carbon precursor, gum ghatti. The synthesized nanopowder has a narrow size distribution of dots (<9 nm) embedded in silica gel with excitation-dependent multi-fluorescence characteristics accountable for the LFs’ solid-state emission. The effectiveness of the CZnO-dots/Si nanopowder in LFs was examined with UV light, fluorescence, and confocal laser scanning microscopy, and the results are discussed herein. Level 1–3 features can also be extracted using the CZnO-dots/Si nanopowder-developed fingerprints. Additionally, nineteen substrates with different surfaces, colours, and natures were chosen to deposit fingerprints, in which the majority of the developed LF substrates completely adsorbed CZnO-dots/Si nanopowder and exposed excellent contrast and visibility. The findings show that the CZnO-dots/Si nanopowder could be an ideal and inexpensive replacement for other commercial powders.