Photochemical Synthesis of Gold Nanorods - Journal of …

This review is concerned with the synthesis of metallic nanoparticles using plant extracts

Seed-Mediated Synthesis of Gold Nanorods: Role of …

The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape. There is a great interest in using nano-colloids for photo-thermal ablation, drug delivery and many other biomedical applications. Gold is particularly used because of its low toxicity. A property of metal nano-colloids is that they can have a strong surface plasmon resonance. The peak of the surface plasmon resonance mode depends on the structure and composition of the metal nano-colloids. Since the surface plasmon resonance mode is stimulated with light there is a need to have the peak absorbance in the near infrared where biological tissue transmissivity is maximal. We present a method to synthesize star shaped colloidal gold, also known as star shaped nanoparticles or nanostars. This method is based on a solution containing silver seeds that are used as the nucleating agent for anisotropic growth of gold colloids. Scanning electron microscopy (SEM) analysis of the resulting gold colloid showed that 70 % of the nanostructures were nanostars. The other 30 % of the particles were amorphous clusters of decahedra and rhomboids. The absorbance peak of the nanostars was detected to be in the near infrared (840 nm). Thus, our method produces gold nanostars suitable for biomedical applications, particularly for photo-thermal ablation.

Journal of Colloid and Interface Science - Elsevier

SiO2--pSt hybrid nanoparticles with each tethered polystyrene possessing molar masses in the range of Mn = 5,000 to 33,000 g/mol were prepared using commercially available silica nanoparticles as colloidal initiators, which greatly facilitated scale-up synthesis. The hybrid particles were characterized both in the solid state and in solution using transmission electron microscopy (TEM) and dynamic light scattering (DLS) respectively. TEM images of the SiO2--pSt colloids revealed the formation of (sub)monolayer patches with interparticle spacing that increased with an increase in the molar mass of the tethered polystyrene. Comparison of the hydrodynamic radii (Rh) of hybrid nanoparticles of varying size determined by DLS in toluene, versus the molar mass (Mn) of the polystyrene chains cleaved from colloids, determined by SEC, revealed a linear relationship. Such a linear dependence of Rh Mn is a strong indication that when the particles are dispersed in toluene, the tethered chains adopt highly chain extended conformations, presumably due to steric interactions caused by the high grafting density. (29)

N2 - The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape. There is a great interest in using nano-colloids for photo-thermal ablation, drug delivery and many other biomedical applications. Gold is particularly used because of its low toxicity. A property of metal nano-colloids is that they can have a strong surface plasmon resonance. The peak of the surface plasmon resonance mode depends on the structure and composition of the metal nano-colloids. Since the surface plasmon resonance mode is stimulated with light there is a need to have the peak absorbance in the near infrared where biological tissue transmissivity is maximal. We present a method to synthesize star shaped colloidal gold, also known as star shaped nanoparticles or nanostars. This method is based on a solution containing silver seeds that are used as the nucleating agent for anisotropic growth of gold colloids. Scanning electron microscopy (SEM) analysis of the resulting gold colloid showed that 70 % of the nanostructures were nanostars. The other 30 % of the particles were amorphous clusters of decahedra and rhomboids. The absorbance peak of the nanostars was detected to be in the near infrared (840 nm). Thus, our method produces gold nanostars suitable for biomedical applications, particularly for photo-thermal ablation.