Li Jiuxing, Zhu Binqing, Yao Xiujie, Zhang Yicong, Zhu Zhi, Tu Song, Jia Shasha, Liu Rudi, Kang Huaizhi, Yang Chaoyong James
The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, the Key Laboratory of Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
ACS Appl Mater Interfaces. 2014 Oct 8;6(19):16800-7. doi: 10.1021/am504139d. Epub 2014 Sep 19.
Attaching thiolated DNA on gold nanoparticles (AuNPs) has been extremely important in nanobiotechnology because DNA-AuNPs combine the programmability and molecular recognition properties of the biopolymers with the optical, thermal, and catalytic properties of the inorganic nanomaterials. However, current standard protocols to attach thiolated DNA on AuNPs involve time-consuming, tedious steps and do not perform well for large AuNPs, thereby greatly restricting applications of DNA-AuNPs. Here we demonstrate a rapid and facile strategy to attach thiolated DNA on AuNPs based on the excellent stabilization effect of mPEG-SH on AuNPs. AuNPs are first protected by mPEG-SH in the presence of Tween 20, which results in excellent stability of AuNPs in high ionic strength environments and extreme pHs. A high concentration of NaCl can be applied to the mixture of DNA and AuNP directly, allowing highly efficient DNA attachment to the AuNP surface by minimizing electrostatic repulsion. The entire DNA loading process can be completed in 1.5 h with only a few simple steps. DNA-loaded AuNPs are stable for more than 2 weeks at room temperature, and they can precisely hybridize with the complementary sequence, which was applied to prepare core-satellite nanostructures. Moreover, cytotoxicity assay confirmed that the DNA-AuNPs synthesized by this method exhibit lower cytotoxicity than those prepared by current standard methods. The proposed method provides a new way to stabilize AuNPs for rapid and facile loading thiolated DNA on AuNPs and will find wide applications in many areas requiring DNA-AuNPs, including diagnosis, therapy, and imaging.
在纳米生物技术中，将硫醇化DNA附着在金纳米颗粒（AuNPs）上极为重要，因为DNA-AuNPs将生物聚合物的可编程性和分子识别特性与无机纳米材料的光学、热学和催化特性结合在一起。然而，目前将硫醇化DNA附着在AuNPs上的标准方案涉及耗时、繁琐的步骤，并且对于大尺寸AuNPs效果不佳，从而极大地限制了DNA-AuNPs的应用。在此，我们基于甲氧基聚乙二醇硫醇（mPEG-SH）对AuNPs的优异稳定作用，展示了一种将硫醇化DNA快速简便地附着在AuNPs上的策略。首先在吐温20存在的情况下，用mPEG-SH保护AuNPs，这使得AuNPs在高离子强度环境和极端pH值下具有出色的稳定性。可以直接将高浓度的氯化钠应用于DNA和AuNP的混合物中，通过最小化静电排斥作用，使DNA高效附着于AuNP表面。整个DNA负载过程只需几个简单步骤，在1.5小时内即可完成。负载DNA的AuNPs在室温下可稳定超过2周，并且它们能够与互补序列精确杂交，可用于制备核-卫星纳米结构。此外，细胞毒性测定证实，通过该方法合成的DNA-AuNPs比通过当前标准方法制备的DNA-AuNPs表现出更低的细胞毒性。所提出的方法为稳定AuNPs以便将硫醇化DNA快速简便地负载到AuNPs上提供了一种新途径，并将在许多需要DNA-AuNPs的领域中得到广泛应用，包括诊断、治疗和成像。
