ORGN 20 |
| Victor H. Perez-Luna, Chemical and Environmental Engineering Department, Illinois Institute of Technology, 10 W.33rd street Perlstein Hall , Room127, Chicago, IL 60616 and Kadir Aslan, Department of Chemical and Environmental Engineering, Illinois Institute of Technology, 10 W. 33 rd street, Chicago, IL 60616. |
| Biotinylation of gold nanoparticles was accomplished using a two-step surface modification procedure. In the first step, a carboxyl-terminated alkane thiol was chemisorbed on the gold nanoparticles, and in the second step these carboxyl groups were further reacted with ((+)-biotinyl-3,6,9,-trioxaundecanediamine) and 2-(2-aminoethoxy)ethanol). This procedure resulted in stable, ligand-modified gold nanoparticles. Upon addition of streptavidin, the biotinylated gold nanoparticles aggregated by means of specific biomolecular recognition. Their aggregation was studied by optical absorption spectroscopy. Controlled aggregation of biotinylated gold nanoparticles resulted in a shift in the surface plasmon resonance peak and broadening of the absorption spectrum of the nanoparticles. The extent of aggregation was found to be dependent on the concentrations of both streptavidin and biotinylated gold nanoparticles. Maximum rate of aggregation was observed when 24 nM of streptavidin and 0.80 nM of biotinylated gold nanoparticles were used. Reversal of nanoparticle aggregation was accomplished by the addition of soluble biotin to the streptavidin-nanoparticle aggregates. Kinetic analysis of the absorbance data showed that streptavidin-induced aggregation of biotinylated gold nanoparticles could be interpreted in terms of a Reaction-Limited Colloidal Aggregation (RLCA) model. This indicates that optical absorption spectroscopy could provide a quantitative measurement of the aggregation process. |
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Molecular Recognition and Self-Assembly
8:20 AM-12:00 PM, Sunday, September 7, 2003 Sheraton New York -- Imperial Ballroom B, Oral
Division of Organic Chemistry |