folate-conjugated gold nanoparticles (synthesis, characterization and design for cancer cells nanotechnology-based targeting)

a new folate-conjugated gold nanoparticle (aunp) has been designed to selectively target the folate receptor that is overexpressed on the surface of tumoral cells. for this purpose, we made 4-aminothiophenol, as a bifunctional linker to react with haucl4 in the presence of sodium borohydride and it was binded to the aunp surface through its thiol group. then, we conjugated amino-terminated nanoparticles to folic acid with an amide-linkage formation. finally, we evaluated the specific interaction between the folic acid and aunp by the corresponding observed characteristic bands in the uv-vis and ftir spectra. transmission electron microscopic (tem) images reveal the spherical aunps formation induced by the bifunctional linker. powder x-ray diffraction (xrd) patterns confirmed the metallic face-centered cubic (fcc) lattice structure with (111), (200), (220), and (311) crystal planes. we estimated the average size of the conjugated nanoparticles to be about 5 nm by tem and xrd. the elemental analysis and atomic absorption showed 59 % organic molecules on the surfaceof aunps