Hantzsch ester modified asymmetric BODIPY probe with ultra-high
sensitivity for ultra-fast detection of endogenous hypochlorite in
living cells
Abstract
Hypochlorite (ClO-) is an important reactive oxygen
species produced by the immune system to fight off invading pathogens,
but its over-expression can interfere with normal physiological process
and induce serious diseases. Although a variety of molecular probes have
been reported for detecting ClO-, the development of
advanced fluorescent tools with faster response and higher sensitivity
to precisely monitor ClO- remains a challenge. In this
work, two Hantzsch ester (a derivative of 1,4-dihydropyridine) derived
fluorescent probes MeDHP-BCl and MeDHP-PhBCl were constructed based on
asymmetric BODIPY-matrix. These probes exhibit significant fluo-rescence
turn-on in the ultra-sensitive (detection limit < 1 nM) and
ultra-fast response (≤ 5 s) to ClO-, the reaction has
determined to be a highly selective N-Chlorination of Hantzsch ester
which cannot be activated by various common bioactive species, including
nitric ox-ide (NO) that could oxidize Hantzsch ester under aerobic
physiological conditions in most reports. MeDHP-PhBCl possess a
relatively longer fluorescence emission wavelength and higher quantum
yield after activation, while more notably, MeDHP-BCl displayed lower
cytotoxicity and more remarkable fluorescence increasement in the
response to ClO-, enabling selective and precise
visualization of endogenous ClO- over-expression in
living RAW264.7 cells.