Development of multi-functional TICT-based fluorescent probe for micro viscosity and latent fingerprint detection

Here in, the TICT-AIE active molecular probe VFP was designed, synthesized, and applied to micro-viscosity sensing and latent fingerprint detection. VFP has a donor-π-acceptor (D-π-A) architecture featuring a quinoline donor and malononitrile acceptor optimized for high fluorescence sensitivity in both the solid and solution phases. In solution, the absorption/emission wavelengths (λ_abs/λ_em) are 399/516 nm with a Stokes shift of 5620 cm^-1, while in the solid state, they red-shift to 425/592 nm and a Stokes shift of 6918 cm^-1. Further, the study observed a red-shifted fluorescence enhancement linked to changes in molecular viscosity during spoilage, with the viscosities of apple, lemon, and orange juices increasing by approximately 7%, 15% and 9% after 9 days of storage at low and room temperatures, respectively. Furthermore, it exhibited strong fluorescence when applied to aged and fresh latent fingerprints from different donors and substrates under various environmental conditions, providing high-contrast visualization across a range of surfaces without lifting, transfer, or additional complex pretreatment or wet-chemical development, revealing clear and intact level 1-3 details. The study presents the potential of photophysical convergence for functional applications across diverse real-world challenges. Finally, treated fingerprints confirm that the VFP probe can preserve touch CTDNA for a complete genetic profile at the next level of study.