Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
Nanotechnology. 2010 Jul 2;21(26):262001. doi: 10.1088/0957-4484/21/26/262001. Epub 2010 Jun 4.
Single molecules in a tunnel junction can now be interrogated reliably using chemically functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode ('tethered molecule-pair' configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the 'free-analyte' configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules.
现在，可以使用化学功能化电极可靠地检测隧道结中的单个分子。监测与一个电极上的配体结合的配体和与其目标结合的第二个电极之间的随机结合波动（“连接的分子对”构型）可以深入了解分子间键合的性质，并定义了重现性隧道数据的要求。模拟表明，在大电流下，隧道间隙存在不稳定性，这导致了多个接触，相应地，测量电流也会有所扩展。在小电流（即大间隙）下，间隙是稳定的，并且用识别试剂对一对电极进行功能化（“自由分析物”构型），当分析物分子被困在间隙中时，可以产生明显的隧道信号。这在化学和电子学之间开辟了一个新的界面，对快速测序单链 DNA 分子具有直接的影响。
