Direct measurements of DNA-mediated colloidal interactions and their quantitative modeling
Direct measurements of DNA-mediated colloidal interactions and their quantitative modeling
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DOI：
10.1073/pnas.1109853108
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发表时间：
2011-09-20
影响因子：
11.1
通讯作者：
Crocker, John C.
中科院分区：
文献类型：
--
作者：
Rogers, W. Benjamin;Crocker, John C.
DNA桥接可用于诱导小颗粒之间的特定吸引力，提供了一种高度通用的方法来创建具有各种周期性结构的独特的基于颗粒的材料。令人惊讶的是，考虑到溶液中DNA链的热力学已经完全理解，现有的DNA诱导粒子相互作用模型通常在强度上误差超过一个数量级，并且在温度依赖性上误差为2倍。这种差异阻碍了设计最有趣的应用所需的复杂温度，序列和时间依赖性相互作用的努力，例如具有高度复杂或多组分微结构或重新配置或自我复制能力的材料。在这里，我们报告的高空间分辨率测量DNA诱导的聚苯乙烯微球之间的相互作用，结合强度相当于自组装实验中使用的，高达6 k（B）T。我们还描述了一个概念上简单，数值上易于处理的模型，定量捕获这些DNA诱导的相互作用的分离依赖性和温度依赖性的强度，没有经验校正。当描述更复杂和实际相关的情况下，接枝的DNA刷与自相互作用，与粒子间桥的形成竞争时，这个模型同样成功。总之，我们的研究结果激发了一种纳米材料设计方法，在这种方法中，可以通过计算找到独特的功能结构，然后在实验中可靠地实现。
DNA bridging can be used to induce specific attractions between small particles, providing a highly versatile approach to creating unique particle-based materials having a variety of periodic structures. Surprisingly, given the fact that the thermodynamics of DNA strands in solution are completely understood, existing models for DNA-induced particle interactions are typically in error by more than an order of magnitude in strength and a factor of two in their temperature dependence. This discrepancy has stymied efforts to design the complex temperature, sequence and time-dependent interactions needed for the most interesting applications, such as materials having highly complex or multicomponent microstructures or the ability to reconfigure or self-replicate. Here we report high-spatial resolution measurements of DNA-induced interactions between pairs of polystyrene microspheres at binding strengths comparable to those used in self-assembly experiments, up to 6 k(B)T. We also describe a conceptually straightforward and numerically tractable model that quantitatively captures the separation dependence and temperature-dependent strength of these DNA-induced interactions, without empirical corrections. This model was equally successful when describing the more complex and practically relevant case of grafted DNA brushes with self-interactions that compete with interparticle bridge formation. Together, our findings motivate a nanomaterial design approach where unique functional structures can be found computationally and then reliably realized in experiment.