A new HS-specific near-infrared fluorescence-enhanced probe that can visualize the HS level in colorectal cancer cells in mice.

Near-infrared (NIR) fluorescence-based sensors capable of selective detection of HS would be useful tools to understand the mechanisms of diseases. A new NIR fluorescence probe was developed for the detection of endogenous HS in colorectal cancer cells in mice. displayed an 87-fold fluorescence enhancement at 796 nm (with excitation at 730 nm) when reacted with HS in a buffer (pH 7.4). was water-soluble, cell-membrane-permeable, had low cytotoxicity and high selectivity and sensitivity for HS. The properties of enable its use in monitoring endogenous HS in living cells, tissues, and mice. The bioimaging results indicated that (1) d-Cys could induce endogenous HS production in living cells and stimulate angiogenesis; (2) tail intravenous injection of into mice generated strong fluorescence in the liver while intraperitoneal injection of d-Cys could further enhance fluorescence in the liver ; (3) importantly, endogenous HS in colorectal cancer cells (HCT116, HT29) and in murine tumor models could be quickly and selectively detected by intratumoral injection of . These results indicated that our new probe could serve as an efficient tool for the detection of cellular HS in living animals and even for cancer diagnosis.