A sensitive near-infrared fluorescent probe for caspase-mediated apoptosis: Synthesis and application in cell imaging

Abstract

Near-infrared (NIR) absorbing dyes represent an intriguing avenue for extracting biological information from living subjects since they can be monitored with noninvasive optical imaging techniques. We designed and synthesized an imaging agent which contains a NIR fluorochrome (IR780) and peptidyl fluoromethyl ketone (FMK) for caspase-9 imaging of cells undergoing apoptosis. The IR780-FMK fluorescent probe had a Strokes shift of 79 nm and quantum yield 0.75. Prostate cancer DU145 cells undergoing apoptosis were successfully imaged using as little as 0.1 μM of IR780-FMK.