Activatable nanoscale metal-organic framework for ratiometric photoacoustic imaging of hydrogen sulfide and orthotopic colorectal cancer in vivo

Nanoscale metal-organic frameworks (nano MOFs) have emerged as a promising biomedical nanoplatform because of their unique properties. However, the exploration of nano MOFs in photoacoustic (PA) imaging is still limited. Here, a novel hydrogen sulfide (H 2 S)-activated nano copper-based MOF (Cu-MOF) was developed as a near-infrared (NIR) ratiometric PA probe for in vivo monitoring of endogenous H 2 S level and orthotopic colorectal cancer imaging via in situ reaction of nano Cu-MOFs with endogenous H 2 S that is closely associated with tumor growth and proliferation in colon cancer. The synthesized nano Cu-MOFs displayed excellent PA responsiveness towards tumor H 2 S level with high selectivity and rapid kinetics. The result suggests the developed probe may provide a unique opportunity to investigate the malignant behaviors of H 2 S-associated events in vivo .