Wu Kun-Ta, Feng Lang, Sha Ruojie, Dreyfus Rémi, Grosberg Alexander Y, Seeman Nadrian C, Chaikin Paul M
Center for Soft Matter Research, New York University, New York, New York, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Aug;88(2):022304. doi: 10.1103/PhysRevE.88.022304. Epub 2013 Aug 12.
DNA-functionalized particles are promising for complex self-assembly due to their specific controllable thermoreversible interactions. However, there has been little work on the kinetics and the aggregation rate, which depend on the rate of particle encounters and the probability that an encounter results in particles sticking. In this study, we investigate theoretically and experimentally the aggregation times of micron-scale particles as a function of DNA coverage and salt concentration. Our 2-μm colloids accommodate up to 70,000 DNA strands. For full coverage and high salt concentration, the aggregation time is 5 min while for 0.1 coverage and low salt it is 4 days. A simple model using reaction-limited kinetics and experimental oligomer hybridization rates describes the data well. A controlling factor is the Coulomb barrier at the nanometer scale retarding DNA hybridization. Our model allows easy measurements of microscopic hybridization rates from macroscopic aggregation and enables the design of complex self-assembly schemes with controlled kinetics.
由于其特定的可控热可逆相互作用，DNA功能化颗粒在复杂自组装方面具有广阔前景。然而，关于动力学和聚集速率的研究较少，这取决于颗粒相遇的速率以及相遇导致颗粒黏附的概率。在本研究中，我们从理论和实验两方面研究了微米级颗粒的聚集时间与DNA覆盖率和盐浓度的函数关系。我们的2微米胶体最多可容纳70000条DNA链。对于完全覆盖和高盐浓度，聚集时间为5分钟，而对于0.1的覆盖率和低盐浓度，聚集时间为4天。一个使用反应受限动力学和实验性寡聚物杂交速率的简单模型能够很好地描述这些数据。一个控制因素是纳米尺度上阻碍DNA杂交的库仑势垒。我们的模型允许从宏观聚集中轻松测量微观杂交速率，并能够设计具有可控动力学的复杂自组装方案。
