Time-Gated Imaging of Latent Fingerprints and Specific Visualization of Protein Secretions via Molecular Recognition.

Persistent nanophosphors can remain luminescent after excitation ceases; thus, they offer a promising way to avoid background fluorescence interference in bioimaging. In this work, Zn2GeO4:Ga,Mn (ZGO:Ga,Mn) persistent luminescence nanoparticles were developed and they were employed for time-gated imaging of latent fingerprints (LFP). The nanoparticles were functionalized with a carboxyl group and utilized to label LFP through reacting with the amino group in the LFP. Results proved the potent ability of ZGO:Ga,Mn in eliminating background fluorescence to afford highly sensitive LFP imaging. Moreover, LFP aged for 60 days were successfully detected due to the presence of highly stable amino acids. After being functionalized with concanavalin A, the nanoparticles achieved visualization of glycoproteins in LFP. This strategy provides great versatility in LFP imaging and good potential in uncovering the chemical information within LFP, making it valuable in forensic investigations and medical diagnostics.