Time Dependent Growth of Gold Nanoparticles: Experimental Corre-lation of van der Waals Contact between DNA and Amino Acids with Polar Uncharged Side Chains

Time-dependent investigation of growth reactions from 0.45 nM gold nanoparticle seeds in the presence of 9 mM amino acids containing polar uncharged side chain (AApusc) serine (Ser), threonine (Thr), asparagine (Asn), and glutamine (Gln) resulted in the formation of aggregated nanostructures either via slow or fast processes. Ser showed immediate aggregation of gold nanoparticles after the growth reaction, while aggregation with Gln, Asn, and Thr was much slower. This slow or fast time-dependent process was directly related to the van der Waals volumes of these amino acids. The aggregation reaction was inhibited by the addition of 600 nM amine-modified DNAs (NH2-PR: NH2(CH2)6-5′-ACATCAGT-3′ and NH2-MR: NH2(CH2)6-5′-TCTTCTGT-3′) prior to the addition of 9 mM amino acids before the growth reaction. The van der Waals contact between DNA and amino acids was examined for the controlled growth process after 12 h in the presence of the critical concentrations of both DNAs for all the four amino acids. The trend ...