Gold nanoparticle probes: Design and in vitro applications in cancer cell culture

A new architecture has been designed by the conjugation of [18F]2-fluoro-2-deoxy-d-glucose (18F-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 18F-FDG by nucleophilic fluorination. For the conjugation of 18F-FDG and AuNPs, cysteamine was first bound to mannose triflate (Man-CA) before synthesizing of 18F-FDG which has cysteamine sides (18FDG-CA). Then, 18FDG-CA was reacted with HAuCl4 to obtain AuNPs and with NaBH4 for reduction of AuNPs. At the end of this procedure, AuNPs were conjugated to 18F-FDG via disulphide bonds (18FDG-AuNP). For the conjugation of Anti-MTDH, 1,1′-carbonyl diimidazol (CDI) was bound to the 18FDG-AuNP, and Anti-MTDH was conjugated via CDI (18FDG-AuNP-Anti-MTDH). This procedure was also performed by using Na19F to obtain non-radioactive conjugates (19FDG-AuNP-Anti-MTDH). Scanning electron microscopy (SEM) images demonstrated that synthesized particles were in nano sizes. 18FDG-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 18FDG-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.