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

Abstract

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 (AA pusc ) 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 (NH 2 -PR: NH 2 (CH 2 ) 6 -5′-ACATCAGT-3′ and NH 2 -MR: NH 2 (CH 2 ) 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 in the NH 2 -PR amount for inhibition of aggregation followed the opposite trend of van der Waals contacts between DNA and amino acids. The difference between NH 2 -PR and NH 2 -MR amounts in the aggregation inhibition process was mainly controlled by the specific two sets of favorable or derogatory van der Waals contacts between amino acids with adenine or thymine of DNAs.

Comparison Investigation on the Adsorption Affinity of DNA Molecules to the Gold Surface Based on the Kinetic and Thermodynamic Analysis of 4-Nitrophenol Reduction

“…DNA-modified or mediated gold nanoparticle (AuNP) conjugates are excellent materials, which are used in a variety of applications, such as identification of single point DNA mutations, synthesis or assembly of materials, − and biosensors. − Adsorption of DNA on the AuNP surface is often the first step, which can be achieved either noncovalently or covalently . The noncovalent attachment is very effective, stable enough during the storage and handling of DNA–AuNPs, and noncostly chemical manipulations with DNA .…”