Gold nanoparticle probes: design and in vitro applications in cancer cell culture.

A new architecture has been designed by the conjugation of [(18)F]2-fluoro-2-deoxy-D-glucose ((18)F-FDG), gold nanoparticles (AuNPs), and anti-metadherin (Anti-MTDH) antibody which is specific to the metadherin (MTDH) over-expressed on the surface of breast cancer cells. Mannose triflate molecule is used as a precursor for synthesis of (18)F-FDG by nucleophilic fluorination. For the conjugation of (18)F-FDG and AuNPs, cysteamine was first bound to mannose triflate (Man-CA) before synthesizing of (18)F-FDG which has cysteamine sides ((18)FDG-CA). Then, (18)FDG-CA was reacted with HAuCl(4) to obtain AuNPs and with NaBH(4) for reduction of AuNPs. At the end of this procedure, AuNPs were conjugated to (18)F-FDG via disulphide bonds ((18)FDG-AuNP). For the conjugation of Anti-MTDH, 1,1'-carbonyl diimidazol (CDI) was bound to the (18)FDG-AuNP, and Anti-MTDH was conjugated via CDI ((18)FDG-AuNP-Anti-MTDH). This procedure was also performed by using Na(19)F to obtain non-radioactive conjugates ((19)FDG-AuNP-Anti-MTDH). Scanning electron microscopy (SEM) images demonstrated that synthesized particles were in nano sizes. (18)FDG-AuNP-Anti-MTDH conjugate was characterized and used as a model probe containing both radioactive and optical labels together as well as the biological target. The (18)FDG-AuNP-Anti-MTDH conjugate was applied to MCF7 breast cancer cell line and apoptotic cell ratio was found to be increasing from 2% to 20% following the treatment. Hence, these results have promised an important application potential of this conjugate in cancer research.