Protein nanoparticles (NPs) based on endogenous biopolymers are promising platform for bioimaging and advanced therapy since they are biocompatible, biodegradable and have low systematic toxicity with high loading capacity. In this work we studied albumin NPs loaded with three cyanine dyes: ICG, IR-806 and IR-820 for colloidal and optical properties. We demonstrated that cross-linked albumin nanoparticles functionalized with IR dyes were promising for optical bioimaging in biotissue transparency window (700-1700 nm). The proposed dye-loaded NPs were of low toxicity in vitro and could be promising for in vivo applications.