Ball-Milling-Assisted Coating and Magnetic Properties of Fluorescent Biodegradable Powders for Fingerprint Detection

The development of environmentally friendly materials for forensic applications is a growing area of interest. Traditional forensic methods often rely on resource-intensive processes and hazardous materials, and thus a demand for sustainable efficient materials without compromising performance is needed. Fluorescent, regular and magnetic powders were prepared through ball-milling-assisted coating using biodegradable matrices such as silica, chitosan, and tri-sodium citrate. The effect of the magnetic core on the optical properties, along with the influence of matrix type on the photophysical and magnetic properties of the powders, was assessed. The results suggest that the polymeric matrix effectively prevented fluorescence quenching, although a reduction in fluorescence intensity was observed when comparing magnetic and non-magnetic powders. For core-shell structures based on chitosan and tri-sodium citrate, the reduction in fluorescence caused by the absorption of the magnetic core (Fe₃O₄) was less pronounced. Additionally, these structures exhibited better magnetic properties when compared with a silica-based core-shell. All fluorescent powders proved highly efficient in fingerprint detection on various surfaces, yielding similar results to commercially available powders. The produced powders are not only safe and cost-effective but also environmentally friendly, making them an alternative to the current commercial powders used in forensic applications.