Analysis of charge transfer and I-V property for the DNA chip by quantum chemical calculations

电化学DNA芯片通过检测单链或双链DNA的电荷电导率变化来确定DNA碱基的序列。实验发现，双链dna比单链dna传导更大的电流。为了深入了解导致这种电荷电导率差异的潜在机制，通过分子动力学和分子轨道（MO）计算，从理论上研究了单链和双链dna的空穴/电子电导率。根据边界MO能级估计了相邻DNA碱基之间的空穴/电子转移积分。单链和双链DNA的电流-电压特性，由每个DNA碱基的转移积分和位点能量得出，定性地与实验一致。

Electrochemical DNA chips determine the sequence of DNA bases by detecting the change in charge conductivity through single- or double-strand DNA. Experimentally, double-strand DNAs were found to conduct much greater electric current than single-strand DNAs. To gain insight into the underlying mechanism leading to such a disparity in charge conductivity, the hole/electron conductivities in single- and double-strand DNAs were theoretically examined by molecular dynamics and molecular orbital (MO) calculations. The hole/electron transfer integrals between the neighboring DNA bases were estimated from the frontier MO energy levels. The current-voltage characteristics of single- and double-strand DNAs, derived from the transfer integrals and the site energy of each DNA base, are qualitatively in agreement with experiment.