Non-base pairing DNA provides a new dimension for controlling aptamer-linked nanoparticles and sensors
Non-base pairing DNA provides a new dimension for controlling aptamer-linked nanoparticles and sensors
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DOI：
10.1021/ja072075
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发表时间：
2007-07-11
影响因子：
15
通讯作者：
Lu, Yi
中科院分区：
文献类型：
--
作者：
Liu, Juewen;Lu, Yi
DNA适体作为一种简单、快速的比色传感器，近年来已被广泛应用。这些系统的一个独特特征是在DNA功能化纳米颗粒上的DNA适体和间隔区中存在非碱基配对寡核苷酸。我们在这里报告一个系统的研究腺苷适体连接的金纳米粒子系统。当适体突出端和间隔区在同一侧对齐时，腺苷响应性拆卸被抑制。这种抑制作用随着间隔区的长度而增加，并且在含有多于三个核苷酸的间隔区的情况下观察到完全抑制的活性。与没有突出端的双链DNA系统中间隔区长度和解链温度之间的线性关系相反，适体系统显示出非线性关系，解链温度随间隔区长度呈指数下降。对照实验表明，这种抑制作用是由于热力学因素，而不是动力学陷阱。与适体信标系统的比较表明，纳米颗粒可能在这种抑制作用中发挥重要作用，并且未检测到适体突出端和间隔子之间的特异性相互作用。间隔区中核苷酸的身份不影响结论。此外，在较低的温度或较高的离子强度下，分解或颜色变化的速率较慢，但受pH值从5.2到9.2的影响很小。因此，除了pH、温度或离子强度之外，非碱基配对DNA提供了控制DNA连接的纳米颗粒的另一个维度，并且这一知识导致了用于传感应用的最佳构建体。
DNA aptamers have been recently applied as simple and fast colorimetric sensors for a wide range of molecules. A unique feature of these systems is the presence of non-base pairing oligonucleotides in both DNA aptamers and spacers on DNA-functionalized nanoparticles. We report here a systematic investigation on an adenosine aptamer-linked gold nanoparticle system. When the aptamer overhang and the spacer were aligned on the same side, adenosine-responsive disassembly was inhibited. This inhibition effect increased with the length of the spacer, and fully inhibited activity was observed with the spacer containing more than three nucleotides. In contrast to a linear relationship between the spacer length and melting temperature in double-stranded DNA systems without overhangs, the aptamer system displayed a nonlinear relationship, with the melting temperature decreasing exponentially with spacer length. Control experiments suggested that this inhibition effect was due to thermodynamic factors rather than kinetic traps. A comparison with aptamer beacon systems indicated that nanoparticles may play an important role in this inhibition effect, and no specific interactions between the aptamer overhang and spacer were detected. The identity of nucleotides in the spacer did not affect the conclusions. Furthermore, the rate of disassembly or color change was slower at lower temperature or higher ionic strength, but was little affected by pH from 5.2 to 9.2. Therefore, non-base pairing DNA provided another dimension for controlling DNA-linked nanoparticles in addition to pH, temperature, or ionic strength, and this knowledge has resulted in the most optimal construct for sensing applications.