Greener Approach Supported Nitrogen-Infused Carbon Dots for Biocompatible Cellular Markers and Fluorescent Ink Based Spray-Assisted Fingerprint Analysis.

we successfully developed a new class of nitrogen-doped carbon dots (N-CDs) using a unique combination of hyaluronic acid (HA), citric acid (CA), and urea. This synthesis, achieved through an efficient one-pot hydrothermal process, has ushered in a new era for bio-imaging and forensic science applications. The N-CDs, characterized techniques such as Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Photoluminescence Spectroscopy (PL), demonstrated outstanding fluorescence properties. These properties were maintained under various pH levels and even under prolonged UV exposure, showcasing their remarkable stability. The transformative potential of these N-CDs was further evidenced in their biocompatibility and efficacy in bio-imaging. When tested in vitro with human cell lines, the N-CDs not only exhibited efficient cellular uptake but also ensured minimal cytotoxicity, marking a significant advancement in safe and effective bio-imaging techniques. Moreover, in the realm of forensic science, the N-CDs proved to be a game-changer for latent fingerprint analysis. Their application on glass surfaces revealed minute fingerprint details, such as ridges and sweat pores, with unprecedented clarity. This exceptional performance is attributed to their luminous properties and their interaction with amino acids and proteins present in fingerprint residues. Our findings pave the way for these N-CDs, synthesized from HA, CA, and urea, to be recognized as versatile and powerful tools. They hold immense promise not only in advancing bio-imaging methodologies but also in revolutionizing forensic techniques for latent fingerprint detection across various surfaces. This study, therefore, presents a significant leap forward in both biomedical and forensic science fields, demonstrating the far-reaching applications of these innovative nanocomposites. [ABSTRACT FROM AUTHOR]