. As a result, the effective and precise monitoring of CTSB activity offers a way out.
Taking this into account, a research team from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences used photoacoustic (PA) imaging for CTSB in tumor detection in a new study.
PA imaging is a new type of non-invasive and non-ionizing biomedical imaging method, which has a huge potential in biomedical research and disease diagnosis due to its excellent tissue-penetrating depth and high spatial resolution.
Using the self-assembly signal enhancement of PA imaging probe, they designed a CTSB-activatable near-infrared PA probe Val-Cit-Cys(SEt)-Lys(Cypate)-CBT (Cypate-CBT).
When Cypate-CBT enters CTSB-overexpressing tumor cells, its disulfide bond is reduced by intracellular glutathione, and its specific cleavage substrate Val-Cit is cleaved by CTSB to produce Cypate-CBT-Cleaved, which undergoes an intermolecular CBT-Cys click reaction to yield Cypate-CBT-Dimer.
The Cypate-CBT-Dimer then self-assembles into near-infrared nanoparticles Cypate-CBT-NPs.
This approach effectively increases local probe concentration, prolongs the retention time, and enhances the PA signal of the probe for CTSB activity imaging.
They also found that compared with unmodified Cypate, the newly designed probe showed a 4.9-fold and 4.7-fold PA signal enhancement in CTSB-overexpressing MDA-MB-231 cancer cells or tumors respectively.
Source: Medindia
