Aggregation-induced fluorescence 'turn on' imaging for fingerprints by an amphiphilic probe: Synthesis and...

Fingerprints are important biological details and play an important role in identifying personal information. To assist the identification of latent fingerprints (LFPs) which are the frequently-met cases in practical application, LFPs are usually made visible/detectable by development (imaging) techniques. In this work, an amphiphilic probe (denoted as HNP) was designed and synthesized. Its amphiphilic nature was confirmed by its single crystal structure and lipid-water partition coefficient (P = 1.38). It showed good solubility in water and bright red AIE (aggregation-induced emission) emission upon visible light excitation (∼410 nm), which satisfied the requirements for LFPs development/imaging. Photophysical parameters (absorption spectrum, emission spectrum, and emission quantum yield), LFPs imaging performance and bio-safety of probe HNP were discussed and reported. It was found that HNP showed efficient AIE effect in aggregated state. After meeting the lipids in LFPs, HNP AIE effect was activated, showing emission "turn-on" phenomenon and LFPs pattern. This mechanism was confirmed by micromorphology analysis. Corresponding dynamics were discussed as well. Good stability and durability were observed for HNP development/imaging. Details down to level 3 were successfully retrieved with high contrast.