title: Experimental studies on the interactions between Au nanoparticles and amino acids: bio-based formation of branched linear chains.
abstract: Biomacromolecules represent new structures employed for the fabrication, assembly, and subsequent use of nanomaterials for a variety of applications. By genetically selecting for the binding abilities of these bio-based molecules, the generation of materials with enhanced and environmentally sound properties is possible. Unfortunately, the level of understanding as to how the biomolecules bind and arrange on the nanomaterial surface is incomplete. Recent experimental and theoretical results suggest that the binding is dependent upon the peptide composition, sequence, and structure; however, these results were obtained for two-dimensional surfaces of the targeted inorganic material. Changing of the sample from two-dimensional targets to in solution three-dimensional nanomaterials presents a challenge because the level of analytical characterization for the latter system is minimal. Here we present our recent studies on the interactions between Au nanoparticles and the amino acid arginine. In our experimental design, the introduction of increasing concentrations of arginine to citrate-capped Au nanoparticles resulted in the formation of branched linear chains of the spherical nanomaterials. This assembly process was able to be monitored using UV-vis spectroscopy, transmission electron microscopy, and dynamic light scattering. The final results suggest that incomplete substitution of the original citrate surface passivant with the amino acid occurs, resulting in surface segregation of the two species. The segregation effect produces a dipole across the Au nanoparticle surface to drive the linear assembly of the materials in solution. Such results can possibly be exploited in understanding binding motifs and modes for biomolecules on the surface of functional nanomaterials.
authors.affiliation: Department of Chemistry, University of Kentucky, 101 Chemistry-Physics Building, Lexington, Kentucky 40506-0055, USA.
authors.forename: Manish
authors.initials: M
authors.lastname: Sethi
authors.forename: Marc R
authors.initials: MR
authors.lastname: Knecht
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D003460:Crystallization / Q000379:methods; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000596:Amino Acids; D001672:Biocompatible Materials; D006046:Gold