this invention relates to a highly effective nanoparticle system for stabilizing near - infrared fluorescent dyes such as indocyanine in order to enhance the dye &# 39 ; s utility for biomedical application . this invention further relates to nanoparticles comprised of biodegradable polymer materials such as poly . the invention also relates to methods of preparing the nanoparticle - entrapped dyes , as well as methods for using them in bioimaging , diagnosis , and treatment of disease . the present invention also relates to compositions and kits comprising nanoparticle - entrapped dyes .