Highly Stable PEGylated Gold Nanoparticles in water: Applications in biology and catalysis

K. Rahme, M.T. Nolan, T. Doody, G.P. McGlacken, C. O’Driscoll, J.D. Holmes
Notre Dame University (NDU), LB

Keywords: gold nanoparticles, stabilisation, polyethylene glycol (PEG), Suzuki cross coupling and homocoupling reaction, cytotoxicty

Summary:

Gold nanoparticles (Au NPs) with diameters ranging between 5-60 nm have been synthesised in water. Functionalised polyethylene glycol-based thiol polymers (mPEG-SH) were used to stabilise the pre-synthesised Au NPs. The grafting density of different PEG length onto AuNPs was determined using either Thermogravimetric analysis (TGA) or Size distribution and Zeta Potential measurements. AuNPs-PEG hybrids were tested as catalyst for Suzuki homocoupling of 4-methoxyphenylboronic acid or phenylboronic acid reaction in water. Stabilty was also assesed in biological fluid and in the presence of siRNA, Finally the cytotoxicty effect on different cell lines were Evaluated. The pre-synthesised AuNPs-PEG has shown size and stability dependent catalytic effects, were AuNps with diameter < 30 nm were only found to be effective catalyst compared to bigger nanoparticles. AuNPs-PEG was also very stable in biological fluid and a not cytotoxic. These results make AuNPs-PEG attractive for further applications in green chemistry catalysis and biology.