Polarity control for nonthiolated DNA adsorption onto gold nanoparticles.
Polarity control for nonthiolated DNA adsorption onto gold nanoparticles.
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DOI：
10.1021/la400617u
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
Xu Zhang;Biwu Liu;M. Servos;Juewen Liu
中科院分区：
文献类型：
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作者：
Xu Zhang;Biwu Liu;M. Servos;Juewen Liu
用巯基化DNA功能化的金纳米颗粒（AuNPs）已经使纳米科学中的许多研究成为可能。金纳米粒子的强巯基/金亲和力和纳米级曲率允许附着的DNA适应有利于杂交的直立构象。最近，它已被证明，非巯基化的DNA也可以通过DNA碱基吸附连接。如果没有巯基标记，DNA的两端甚至内部碱基都可能被吸附，从而降低后续分子识别反应的特异性。在这项工作中，我们采用模块化序列设计方法，系统地研究了DNA序列对吸附极性的影响。多聚腺嘌呤（poly-A）的嵌段可用于实现高密度的DNA附着。当poly-A嵌段长度较短时（例如，低于5-7）时，负载与嵌段长度无关，并且缀合物不能有效地与其cDNA杂交，这表明由吸附动力学控制的随机附着。增加嵌段长度导致降低的容量，但提高杂交，这表明更多的DNA与所需的构象被吸附，由于聚-A结合的热力学效应。通过包括富含T或G的加帽序列可以进一步改进设计。最后，描述了一种更通用的双链DNA方法，适用于不能满足上述设计要求的DNA。
Gold nanoparticles (AuNPs) functionalized with thiolated DNA have enabled many studies in nanoscience. The strong thiol/gold affinity and the nanoscale curvature of AuNPs allow the attached DNA to adapt an upright conformation favorable for hybridization. Recently, it has been shown that nonthiolated DNA can also be attached via DNA base adsorption. Without a thiol label, both ends of the DNA and even internal bases could be adsorbed, decreasing the specificity of subsequent molecular recognition reactions. In this work, we employed a modular sequence design approach to systematically study the effect of DNA sequence on adsorption polarity. A block of poly adenine (poly-A) could be used to achieve a high density of DNA attachment. When the poly-A block length is short (e.g., below 5-7), the loading was independent of the block length, and the conjugate cannot hybridize to its cDNA effectively, suggesting a random attachment controlled by adsorption kinetics. Increasing the block length leads to reduced capacity but improved hybridization, suggesting that more DNA with the desired conformation was adsorbed due to the thermodynamic effects of poly-A binding. The design can be further improved by including capping sequences rich in T or G. Finally, a more general double-stranded DNA approach was described to be suitable for DNA that cannot satisfy the above-mentioned design requirements.