Gynura Cusimba‐Derived Nitrogen‐Doped Carbon Dots/ZnO Nanocomposite: A Biocompatible Alternative for Detecting Latent Fingerprints

Abstract To address the present need in forensic security perceptions, including the ability to detect latent fingerprints, designing and development of low‐cost fluorescent materials becomes inevitable. This work illustrates the preparation of ZnO and its nanocomposite, Zn−CD with nitrogen doped carbon dots (CD−GC) with all components being generated from a single natural precursor, “Gynura Cusimba”. Cell viability experiment carried out on HEK 293T cell line revealed that CD−GC, pure ZnO nanoparticles, and Zn−CD_0.8 were all biocompatible after being suitably evaluated by various analytical methods. Zn−CD_0.8 nanopowder was useful in detecting level 1–3 features of latent fingerprint developed on several substrates, which displayed good contrast and visibility. The work also highlights the application of Zn−CD_0.8 nanopowder for real time detection of latent fingerprints by demonstrating its use to identify aged fingerprints and those immersed in water. The results indicate that the potential of Zn−CD_0.8 to be a reasonably priced alternative to the existing commercial powders.