Zhang Jian, Malicka Joanna, Gryczynski Ignacy, Lakowicz Joseph R
Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, Maryland 21201, USA.
J Phys Chem B. 2005 Apr 28;109(16):7643-8. doi: 10.1021/jp0490103.
Tiopronin monolayer-protected silver nanoparticles with different core sizes (average diameter = 2, 5, 20 nm) were prepared by using different mole ratios of silver nitrate/tiopronin. Ligands on the silver particles were partially displaced by fluorescein-labeled thiolate single-stranded oligonucleotides or their complementary unlabeled oligonucleotides through ligand exchange. The fluorophores on silver particles showed a surface-enhanced fluorescence (SEF) dependent on the size of metallic cores. The particles could be coupled through hybridizations of oligonucleotides bound on the particles. The coupled particles were aggregated due to multiple displacements of oligonucleotides on each particle, resulting in stronger SEF. The dye-labeled oligonucleotides were assembled on the silver islands on the solid substrate, and the complementary oligonucleotide-displaced particles were coupled via oligonucleotide hybridization. The couplings between particles and islands resulted in an obvious fluorescence enhancement.
通过使用不同摩尔比的硝酸银/硫普罗宁制备了具有不同核尺寸（平均直径 = 2、5、20 纳米）的硫普罗宁单层保护银纳米颗粒。银颗粒上的配体通过配体交换被荧光素标记的硫醇盐单链寡核苷酸或其互补的未标记寡核苷酸部分取代。银颗粒上的荧光团表现出依赖于金属核尺寸的表面增强荧光（SEF）。颗粒可以通过结合在颗粒上的寡核苷酸杂交进行偶联。由于每个颗粒上寡核苷酸的多次置换，偶联的颗粒发生聚集，导致更强的 SEF。染料标记的寡核苷酸组装在固体基质上的银岛上，互补的寡核苷酸置换颗粒通过寡核苷酸杂交偶联。颗粒与岛之间的偶联导致明显的荧光增强。
