Characterization of protein aggregated gold nanocrystals

This paper describes the preparation of an aqueous dispersion of electrosta tically stabilized gold nanocrystals. It also describes the characterizatio n of these nanocrystals by NMR, SAXS, SLS, and TEM prior to and following t heir modification by chemisorption of 3-mecaptopropanoic acid. Using the in sights gained, these nanocrystals were subsequently modified by chemisorpti on and appropriate surface concentration of a disulfide biotin analogue (DS BA). Addition of streptavidin to the DSBA-modified gold dispersion results in the binding of gold nanocrystals to opposite faces of the protein and in the aggregation of the dispersion. The growth kinetics and structure of th e resulting aggregates were characterized by W-visible spectroscopy, DLS, S AXS, and TEM. Some implications of these findings for the assembly of compl ex nanocrystal architectures in solution are considered.