Near-infrared fluorescent labeled peptosome for application to cancer imaging.

Nonionic amphiphilic copolypeptides, which were composed of hydrophilic poly(sarcosine) and hydrophobic poly(gamma-methyl L-glutamate) blocks, were synthesized with varying chain lengths of the blocks. The polypeptides having a suitable hydrophilic and hydrophobic balance were found to form vesicular assemblies of 100 nm size in buffer, which was evidenced by the TEM observation, the DLS analysis, and the encapsulation experiment. The genuine peptide vesicles, peptosomes, were labeled with a near-infrared fluorescence (NIRF) probe.