Unconventional Fluorescent Magnetic Mesoporous Microspheres for Visualizing Latent Fingerprints

Abstract

High-resolution visualization of latent fingerprints is key to effectively assessing crime scenes. Unconventional luminophores provide promising application potentials due to facile preparation and excellent biocompatibility, but are rarely reported for imaging latent fingerprints (LFPs). Here, a novel and cost-effective strategy is developed to prepare unconventional fluorescent magnetic mesoporous microspheres (UFMMMs) by growing a mesoporous silicon shell, templated by designed amphipathic unconventional luminescent (N-eicosanoyl-hydroxyproline, C₂₀-HYP) aggregate micelles, on the magnetite core. The obtained UFMMMs with blue unconventional fluorescence and an average diameter of 650 nm can clearly visualize the level 1–3 details of LFPs on different substrates. The outstanding capability in imaging fingerprints results from the combined effects of the fine luminescence, paramagnetism, and high dispersion of UFMMMs. The intermolecular interactions between C₂₀-HYP and amino in UFMMMs enhance the fluorescence intensity by increasing electron delocalization and the proportion of π-electrons. This study provides a new perspective for the controllable construction of fluorescent probes based on unconventional luminophores.