KCS

Saccharides are important biological molecules that play vital roles in nutrition, metabolism, and immunity of living system. Two-photon microscopy (TPM) employing two near-infrared (NIR) photons for excitation offers a number of advantages over OPM, including increased penetration depth (>500 mm), localized excitation, and prolonged observation time.However, there is no report on TP probes for saccharides that can visualize the biological events deep inside the live tissue with TPM. Recently, we reported 2-acetyl-6-(dimethylamino)naphthalene (acedan)-derived TP probes for Mg²⁺ (AMg1), Ca²⁺ (ACa1-ACa3), Zn²⁺ (AZn1 and AZn2), and pH (AH1 and AH2) that can visualize the metal ion distribution and the acidic vesicles in the living tissues. Herein, we extend our earlier work and report TP probe for saccharides (AS1) derived from acedan as the fluorophore and boronic acid as the saccharide binding site. AS1 can be excited by 780 nm laser photons, shows 20-fold enhancement in one- and two-photon excited fluorescence in response to D-fructose, a dissociation constant (K_d^TP) of 50 mM, and can selectively detect intracellular monosaccharides in the live cells and living tissues without interference due to the membrane-bound probes by TPM.