Book Chapter Details
Mandatory Fields
Rahme, K.; Holmes, J. D.
2015 September
Dekker Encyclopedia of Nanoscience and Nanotechnology
Gold nanoparticles: synthesis, characterization, and bioconjugation
Taylor & Francis
London, UK
In Press
Optional Fields
Gold nanoparticles (Au NPs) with diameters ranging between 4 and 150 nm are synthesized in water. The strong reducing agent sodium borohydride was used to produce small Au NPs with diameter about 4 ± 1 nm. Au NPs of 15 and 30 nm were obtained by a slightly modified Turkevich and Frens method using sodium citrate as both reducing and stabilizing agent at high temperature. The attempt to produce Au NPs with diameter larger than 30–40 nm by the Turkevich method resulted in an increase in the polydispersity and the shape diversity of the final Au NPs, indicating the importance of the trial of new reducing agents in the production of Au NPs especially for diameters above 40 nm. Therefore, hydroxylamine-o-sulfonic acid (NH2OSO2OH) was used here for the first time as a new reducing agent for tetrachloroauric acid at room temperature to produce Au NPs with diameter of about 60, 90, and 150 nm. This new method using NH2OSO2OH is an extension of the approaches described to produce Au NPs with diameter above 40 nm by direct reduction. The obtained nanoparticles were characterized using ultraviolet–visible spectroscopy, dynamic light scattering, and transmission electron microscopy. Further bioconjugation on 15, 30, and 90 nm Au NPs were performed by grafting covalently Apolipoprotein E and bovine serum albumin through an ethylene glycol-N hydroxysuccinimide linker (NHS-PEG-S-S-PEG-NHS) making them very attractive for drug delivery and cell targeting. Finally, functionalized polyethylene glycol-based thiol polymers were also used to stabilize the presynthesized Au NPs-PEG-Protein.
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