This invention provides a novel probe, which contains a prostate peptide
substrate. The probe can be used as a prostate diagnostic agent for
optical imaging. An 11 amino acid peptide substrate is synthesized for
specific prostate-specific antigen (PSA). This protected graft copolymer
(PGC) consists of a poly-L-lysine (PL) backbone and methoxypoly(ethylene
glycol) (MPEG). Two terminals of peptide substrate are bound to
poly-L-lysine and Cy5.5 fluorochrome. This probe will be used as a NIR
(near-infrared fluorescence) probe for optical imaging.