Synthesis of small fluorescent molecules for detection of biologically important analytes

Abstract

A novel dithiomaleimide BODIPY (BDP-NGM) probe has been synthesized and characterized where the dithiomaleimide moiety was attached at the meso position. The BDP-NGM shows a “turn-on” fluorescence response upon reaction with ONOO−

In the second study, we synthesize a novel substituent study in the BODIPY (Mes-BOD-SePh) system by embedding a mesitylene moiety at the meso-position of the BODIPY system. The Mes-BOD-SePh shows high selectivity with NaOCl among other ROS/RNS, and gives a “turn-on” response. Surprisingly, in live cell experiments, the probe specifically located and accumulated in lipid droplets and demonstrated a fluorescence “turn-on” response without any addition of analyte. This “turn-on” response due to aggregation-induced emission (AIE).

Two novel organoselenium-based molecules (Probe-1 and Probe-OCl) based on a synthetic intermediate of mycophenolic acid (MPA). Both probes show instant “turn on” fluorescence (< 1 s) upon the addition of OCl-, and are completely soluble in aqueous media. In live cell experiments involving U-2OS cells and HeLa cells, Probe-OCl accumulated and aggregated in lipid droplets (LDs) and gives a “turn-on” fluorescence response even before the addition of OCl-. To overcome the aggregated induced emission effect of the Probe-OCl, another probe based on the MPA moiety has been developed for the selective detection of cysteine.

The 1,8-naphthalimide fluorophore was synthesized by using diphenylphosphinic as a superoxide receptor. The compound (Lyso-nap) has displayed selectivity towards O2•̅ in the lysosome due to the incorporation of morphiline moiety. Lyso-nap exhibit excellent pH stability, high selectivity, and low detection limit (4.0 μM) in aqueous media.

Magnetic Resonance Imaging (MRI) is a noninvasive technique which can provide anatomical detail of inner organs in real time with excellent resolution. To attain selectivity toward pSer262 Gd3+ should be related and conjugated with a monoclonal antibody through interface called spacer. The target of studying protein phosphorylation using MRI techniques can be developed to allow for additional noninvasive imaging options that can be conducted in real time.