A carboxylesterase-selective ratiometric fluorescent two-photon probe and its application to hepatocytes and liver tissues

Abstract

A ratiometric two-photon fluorescent probe for quantitative detection of carboxylesterase activity in live cells and tissues was reported.

Measuring human carboxylesterase 2 activity in pancreatic cancer patient-derived xenografts using a ratiometric fluorescent chemosensor

“…Although other hCES2 fluorescent chemosensors have been reported, probe 2 described here overcomes several limitations that have hindered previous hCES2 chemosensors from providing accurate and practical measurements of hCES2 activity 18–22,25,32–34. First, probe 2 can be readily synthesized following the facile coupling of 3 to benzoyl chloride and demonstrates enhanced selectivity for hCES2 over hCES1 to the extent where Michaelis–Menten parameters for hCES1 could not be measured 21,24,33,34. Second, our sensor demonstrates improved solubility in aqueous media, with a maximal use of 0.5% organic solvent as opposed to 50% organic solvent used in other reported probes 18–22,25.…”

“…temperature and pH), producing substantial background signal when introduced in cells. To overcome these issues, several ratiometric fluorescent probes were constructed to more accurately quantify hCES2 activity in living cells 20–24. However, these probes either have aqueous solubility issues, absorb and emit at short wavelengths, suffer from photostability issues or are poorly selective for hCES2 over hCES1 21,25.…”

Fluorescence imaging of drug target proteins using chemical probes

“…Park et al. [ 30 ] recently reported an ICT-based probe for ratiometric and TP detection of carboxylesterases in both hepatocytes and liver tissues. However, ICT fluorophores are usually sensitive to environmental polarity, which may potentially interfere with the readout of enzyme activity.…”

Fluorescent Probes for the Detection of Enzymatic Activity for Preclinical Applications

“…Fluorescence‐based molecular probes for directly detecting enzymatic activity levels can allow for more accurate measurement, A key part in the design of enzyme‐sensitive molecular probes is to devise fluorophore‐linked substrates to rapidly change fluorescence with enzymatic activity (Figure ( a)), and in recent years, several molecular probes with various structures, targeting different diseases/enzyme systems have been developed …”