Pekcevik Idah C, Poon Lester C H, Wang Michael C P, Gates Byron D
Department of Chemistry and 4D LABS, Simon Fraser University , 8888 University Drive, Burnaby, British Columbia V5A1S6 Canada.
Anal Chem. 2013 Oct 15;85(20):9960-7. doi: 10.1021/ac4027737. Epub 2013 Sep 23.
A quantitative and tunable loading of single-stranded (ss-DNA) molecules onto gold nanorods was achieved through a new method of surfactant exchange. This new method involves the exchange of cetyltrimethylammonium bromide surfactants for an intermediate stabilizing layer of polyvinylpyrrolidone and sodium dodecylsulfate. The intermediate layer of surfactants on the anisotropic gold particles was easily displaced by thiolated ss-DNA, forming a tunable density of single-stranded DNA molecules on the surfaces of the gold nanorods. The success of this ligand exchange process was monitored in part through the combination of extinction, X-ray photoelectron, and infrared absorption spectroscopies. The number of ss-DNA molecules per nanorod for nanorods with a high density of ss-DNA molecules was quantified through a combination of fluorescence measurements and elemental analysis, and the functionality of the nanorods capped with dense monolayers of DNA was assessed using a hybridization assay. Core-satellite assemblies were successfully prepared from spherical particles containing a probe DNA molecule and a nanorod core capped with complementary ss-DNA molecules. The methods demonstrated herein for quantitatively fine tuning and maximizing, or otherwise optimizing, the loading of ss-DNA in monolayers on gold nanorods could be a useful methodology for decorating gold nanoparticles with multiple types of biofunctional molecules.
通过一种新的表面活性剂交换方法，实现了单链（ss-DNA）分子在金纳米棒上的定量且可调节负载。这种新方法涉及用十六烷基三甲基溴化铵表面活性剂交换聚乙烯吡咯烷酮和十二烷基硫酸钠的中间稳定层。各向异性金颗粒上的表面活性剂中间层很容易被硫醇化的ss-DNA取代，从而在金纳米棒表面形成可调节密度的单链DNA分子。部分通过消光光谱、X射线光电子能谱和红外吸收光谱的结合来监测这种配体交换过程的成功与否。通过荧光测量和元素分析相结合的方法，对具有高密度ss-DNA分子的纳米棒上每个纳米棒的ss-DNA分子数量进行了定量，并使用杂交试验评估了用致密DNA单层包覆的纳米棒的功能。从含有探针DNA分子的球形颗粒和用互补ss-DNA分子包覆的纳米棒核心成功制备了核-卫星组装体。本文展示的用于定量微调、最大化或以其他方式优化金纳米棒上单链DNA单层负载的方法，可能是用多种类型生物功能分子修饰金纳米颗粒的有用方法。
