Geballe Laboratory for Advanced Materials, Department of Materials Science and Engineering, Stanford University, Stanford, California, USA.
Biophys J. 2010 Jun 16;98(12):2954-63. doi: 10.1016/j.bpj.2010.03.017.
DNA hybridization at surfaces is a crucial process for biomolecular detection, genotyping, and gene expression analysis. However, hybridization density and kinetics can be strongly inhibited by electric fields from the negatively charged DNA as the reaction proceeds. Here, we develop an electrostatic model to optimize hybridization density and kinetics as a function of DNA surface density, salt concentrations, and applied voltages. The electrostatic repulsion from a DNA surface layer is calculated numerically and incorporated into a modified Langmuir scheme, allowing kinetic suppression of hybridization. At the low DNA probe densities typically used in assays (<10(13)/cm(2)), electrostatics effects are largely screened and hybridization is completed with fast kinetics. However, higher hybridization densities can be achieved at intermediate DNA surface densities, albeit with slower kinetics. The application of positive voltages circumvents issues resulting from the very high DNA probe density, allowing highly enhanced hybridization densities and accelerated kinetics, and validating recent experimental measurements.
DNA 在表面的杂交是生物分子检测、基因分型和基因表达分析的关键过程。然而，随着反应的进行，带负电荷的 DNA 会产生电场，从而强烈抑制杂交的密度和动力学。在这里，我们开发了一种静电模型，以优化杂交的密度和动力学，使其作为 DNA 表面密度、盐浓度和外加电压的函数。通过数值计算来计算 DNA 表面层的静电排斥，并将其纳入改进的 Langmuir 方案中，从而抑制杂交的动力学。在通常用于检测的低 DNA 探针密度(<10(13)/cm(2)))，静电效应基本被屏蔽，并且杂交具有快速的动力学。然而，在中间 DNA 表面密度下，可以实现更高的杂交密度，尽管动力学较慢。施加正电压可以避免由于 DNA 探针密度非常高而导致的问题，从而允许高度增强的杂交密度和加速的动力学，并验证最近的实验测量。
