Enhanced fluorescence imaging of level 1–3 latent fingerprints on multi-materials through lipophilicity-tunable probes

Latent fingerprints (LFPs) are crucial for personal information security and forensic medicine. In recent years, there has been a lot of attention on fluorescence probes for LFP imaging, but the effect of lipophilicity on LFP's imaging performance has not been fully explored. Herein, three naphthalimide-based AIE probes (TPA-NA-Pr, TPA-NA-OH, TPA-COOH) with different lipophilicity were designed and analyzed. After optimizations, TPA-NA-Pr and TPA-NA-OH were found to be able to visualize LFPs within 2 seconds under 405 nm LED lamp excitation. By immersing materials with the probe solution or spraying the probe solution on different material surfaces, a series of high-quality LFP images could be quickly developed. Even LFP level 3 details (such as sweat pores) could be directly observed with naked eyes. The probe solution stored for 2 months did not precipitate or deteriorate, but still can be used for accurate LFP imaging on different substrates with high-resolution level 1–3 details. This study provides insights into the role of lipophilicity on LFP probes and furnishes two LFP probes with extended lifespan and reduced costs for their real-life applications in personal identification and criminal investigation scenarios. [Display omitted] •The impact of probe’s lipophilicity on latent fingerprint imaging quality has been fully explored.•Probe TPA-NA-Pr and TPA-NA-OH can visualize LFPs within 2 s under a portable 405 nm LED lamp.•The probes can offer fine level 1–3 LFP images on multi-material surfaces by soaking or spraying.