A Fluorescence-Based Method for Determining the Surface Coverage and Hybridization Efficiency of Thiol-Capped Oligonucleotides Bound to Gold Thin Films and Nanoparticles

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• 作者：Linette M. Demers ; Chad A. Mirkin ; Robert C. Mucic ; Robert A. Reynolds ; III ; Robert L. Letsinger ; Robert Elghanian ; and Garimella Viswanadham
• 刊名：Analytical Chemistry
• 出版年：2000
• 出版时间：November 15, 2000
• 年：2000
• 卷：72
• 期：22
• 页码：5535 - 5541
• 全文大小：87K
• 年卷期：v.72,no.22(November 15, 2000)
• ISSN：1520-6882

文摘

Using a fluorescence-based method, we have determinedthe number of thiol-derivatized single-stranded oligonucleotides bound to gold nanoparticles and their extentof hybridization with complementary oligonucleotides insolution. Oligonucleotide surface coverages of hexanethiol12-mer oligonucleotides on gold nanoparticles (34 ± 1pmol/cm²) were significantly higher than on planar goldthin films (18 ± 3 pmol/cm²), while the percentage ofhybridizable strands on the gold nanoparticles (1.3 ± 0.3pmol/cm², 4%) was lower than for gold thin films (6 ± 2pmol/cm², 33%). A gradual increase in electrolyte concentration over the course of oligonucleotide depositionsignificantly increases surface coverage and consequentlyparticle stability. In addition, oligonucleotide spacersequences improve the hybridization efficiency of oligonucleotide-modified nanoparticles from ~4 to 44%. Thesurface coverage of recognition strands can be tailoredusing coadsorbed diluent oligonucleotides. This providesa means of indirectly controlling the average number ofhybridized strands per nanoparticle. The work presentedhere has important implications with regard to understanding interactions between modified oligonucleotidesand metal nanoparticles, as well as optimizing the sensitivity of gold nanoparticle-based oligonucleotide detectionmethods.