Rational design of fluorescent nanoparticles: From wavelength redshift to increased water solubility for stable and high-resolution imaging of latent fingerprints

Efficient and accurate visual identification of latent fingerprints is crucial in areas such as criminal investigation and information security. Aggregation-induced luminescence (AIE) fluorescent materials are widely used in this field because of their strong fluorescence and easy functionalization. They have attracted significant interest and emerged as a promising area since the introduction of the AIE concept. Here a new water-soluble fluorescent nanoparticle, flu-p-DITPA, through amphiphilic self-assembly with amphiphilic polymers macro-CTA-mPEG₂₀₀₀ (P1) and exhibits typical AIE properties. The core molecule, indo-DITPA, derived from the triphenylamine backbone, was obtained through rational molecular design and theoretical calculations, and the calculated results were confirmed with experimental results. The photophysical properties of indo-DITPA and flu-p-DITPA have been meticulously studied, revealing their remarkable characteristics. Taking advantage of their favorable photophysical properties, good water solubility, and biocompatibility, the researchers have devised a simple yet effective method for visualizing latent fingerprints (LFPs) with high resolution under UV light. This method enables the easy decoding of latent fingerprint information at primary, secondary, and tertiary levels. Importantly, this technique is simple, rapid, and user-friendly, marking a significant step forward in the field of forensic science and fingerprint analysis.