Researchers have developed a number of potassium ion
(K+) probes to detect fluctuating K+ concentrations during a
variety of biological processes. However, such probes are not
sensitive enough to detect physiological fluctuations in living
animals and it is not easy to monitor deep tissues with
short-wavelength excitations that are in use so far. In a new
report, Jianan Liu and a team of researchers in neuroscience,
chemistry, and molecular engineering in China, describe a highly
sensitive and selective nanosensor for near infrared (NIR) K+ ion
imaging in living cells and animals. The team constructed the
nanosensor by encapsulating upconversion nanoparticles (UCNPs) and
a commercial potassium ion indicator in the hollow cavity of
mesoporous silica nanoparticles and coated them with a K+ selective
filter membrane. The membrane adsorbed K+ from the medium and
filtered away any interfering cations. In its mechanism of action,
UCNPs converted NIR to ultraviolet (UV) light to excite the
potassium ion indicator and detect fluctuating potassium ion
concentrations in cultured cells and in animal models of disease
including mice and zebrafish larvae. The results are now published
on Science Advances.
Highly sensitive nanosensor detects subtle potassium changes
in the brain
