Synthesis and Characterization of Conjugated Gold and Silver Nanoparticles with Sulfur Containing Amino Acids
Metallic particles have distinct optical properties in the UV-visible spectrum. Collective excitation of the electronic cloud at the surface of the particles leads to resonance absorption and scattering. Manipulation of the NP surfaces by attaching antibodies or other ligands (such as vitamins, amino acids) allows the NPs to preferentially target cells which express receptors that correspond to the NPs’ surface ligand. When the surface modified NP reaches the appropriate receptor, it may exploit natural cellular uptake mechanisms causing the NPs to concentrate in desired pathogenic cells. Once concentrated in a region of the human body, for example within a tumor, radiological techniques could be employed for imaging and therapy. However, the organic molecules used to suspend the synthesized nanoparticles in aqueous solutions have been a potential interference. Our current work shows that naked gold nanoparticles (NGNP) can be produced in aqueous solution. Therefore, we propose to synthesize naked gold or silver nanoparticles upon reduction of Au2O3 or Ag2O by acetyl acetone and by hydrogen gas reduction and bind these clean nanoparticles to sulfur containing amino acids. The resulting conjugated NGNP will be characterized by employing transition electron microscope (TEM), dynamic light scattering, electrophoretic mobility, pH meter, conductivity, inductively coupled plasma atomic emission spectroscopy (ICP-OES), and UV-VIS spectra.