Fucoidan, FSD Fluor™ 750 is a NIR fluorescent biopolymer that fucoidan (~30 KDa) is covalently conjugated with FSD Fluor 750.  Fucoidan is a highly sulfated polysaccharide from various species of brown algae and seaweed and known to have nanomolar affinity to P-selectin which is overexpressed on the various cancers, endothelium overlying active atherosclerotic plaques, and activated platelet. FSD 750 is the new generation of NIR dye, developed by BioActs’ cutting-edge technology, that displaying excellent optical property comparing to spectrally similar dyes. FSD 750 might be excited using the 750 nm laser line or dye-pumped laser excitation and the emission occurs at biological tissue permeable NIR region. Fucoidan, FSD Fluor™ 750 can be applicable in fluorescence imaging of various biological studies such as P-selectin overexpression in tumor cells, angiogenic blood vessels in tumors and inflammatory lesions, vulnerable atherosclerotic plaques, platelet-rich thrombus, heart ischemia, etc