Adsorption and hybridization of oligonucleotides on mercaptoacetic acid-capped CdSe/ZnS quantum dots and quantum dot-oligonucleotide conjugates
Adsorption and hybridization of oligonucleotides on mercaptoacetic acid-capped CdSe/ZnS quantum dots and quantum dot-oligonucleotide conjugates
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DOI：
10.1021/la062217y
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发表时间：
2006-12-19
期刊：
影响因子：
3.9
通讯作者：
Krull, Ulrich J.
中科院分区：
文献类型：
--
作者：
Algar, W. Russ;Krull, Ulrich J.
人们对量子点 (QD) 独特光学特性的兴趣导致了用于成像和诊断的 QD 生物共轭物的开发。尽管这些应用很多，但人们对量子点与生物分子之间的相互作用知之甚少。在这项工作中，我们描述了寡核苷酸和用巯基乙酸配体封端的 CdSe/ZnS 量子点之间的氢键相互作用。相互作用的强度可以通过 pH 值和离子强度的变化、甲酰胺的添加以及 ssDNA 和 dsDNA 之间的差异来调节。荧光共振能量转移实验表明，共轭寡核苷酸采用位于量子点表面的构象。氢键相互作用还影响 QD-DNA 缀合物的杂交动力学以及 QD 缀合的 dsDNA 的热稳定性。前者类似于传统的固相杂交，其中更强的寡核苷酸吸附导致更快的动力学。就后者而言，与QD表面的相互作用可以锐化熔解转变并改变dsDNA的熔解温度。当吸附相互作用最小化时，这些效应基本上不存在。
Interest in the unique optical properties of quantum dots (QDs) has resulted in the development QD-bioconjugates for imaging and diagnostics. Although these applications are numerous, considerably less is known about the interactions between QDs and biomolecules. In this work, we describe hydrogen-bonding interactions between oligonucleotides and CdSe/ZnS quantum dots capped with mercaptoacetic acid ligands. The strength of the interactions can be modulated by changes in the pH and ionic strength, the addition of formamide, and differences between ssDNA and dsDNA. Fluorescence resonance energy transfer experiments have shown that conjugated oligonucleotides adopt a conformation that lies across the surface of the QD. The hydrogen- bonding interactions also affect the kinetics of hybridization with QD-DNA conjugates and the thermal stability of QD-conjugated dsDNA. The former is analogous to conventional solid-phase hybridization, where stronger oligonucleotide adsorption leads to faster kinetics. With respect to the latter, interactions with theQD-surface can sharpen the melt transition and alter the melt temperature of dsDNA. These effects are largely absent when adsorptive interactions are minimized.