Gold nanoparticles (AuNPs) with an estimate diameter of 25 nm have been synthesized and characterized using ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS) and Zeta potential measurements. AuNPs were coated with D2B, a monoclonal antibody recognizing an extracellular epitope of the human prostate specific membrane antigen (hPSMA). Binding of D2B to PSMA induces endocytosis of the latter, thereby marking PSMA as a docking site for the delivery of therapeutic agents. To attain a stabilized and covalent bond between D2B and AuNPs, the sulthydryl group (SH) in a cysteine ...