单根单壁碳纳米管上自组装纳米金及其调控信号转换DNA电学生物传感器

Recent year, more attentions have been paid onto the nanogold-based DNA electrical biosensor because of the advantages in sensitivity and flux. Further developing novel type of signal ctransduction technique with ultrasensitivity and ultralow detection limit is the next step by combing the selfassembly property of nanostructured gold and the fabrication of nanodevice. This proposal aims to develop such kind of new electrical DNA biosensor in which the signal transduction is mediated by the nanogold assemled on sing-walled carbon nanotubes(SWNT). The single nanodevice will be fabricated by selfassembling nanostructured gold including nanorod and nanoparticle on in situ grown single SWNT on wafer. The electrical signal through the one-dimensional gold nanowire will begenerated after the extra deposition of gold or other metal on the gold wire because of the diference of absorption of ssDNA and dsDNA on nanogold surfaceNA and target DNA in the presence of a redox system in the solution. Thus, the function of such nanodevice forsensing target DNA with ultrohigh sensitivity and ultralow detection limit will be realized eventually. Based on single SWNT-based devices, multi-devices will be developed. This will be of great significance therotically and practically for developing DNA biosensing technology with high sensitivity,high flux,low detection limit, quick and simple for detecting and screening Single Nucleotide Polymorphisms(SNPs).

近年来，基于纳米金的电学生物传感器由于在检测灵敏度和高通量方面的优势，逐渐引起人们的重视。如何结合纳米金的自组装性能和纳米器件的制作,进一步开发基于纳米金具有超高灵敏度的新型信号转换技术和实现超低检测下限是一个重要的课题。本项目提出基于单根单壁碳纳米管上自组装纳米金的调控信号转换的DNA 电学传感器的研究，通过在基片表面原位生长或转移单根超长单壁碳纳米管，在电场下将合成的纳米金（包括金纳米棒和纳米粒子）自组装在单根超长单壁碳纳米管上，从而构筑单个一维的纳米金组装线纳米器件，通过DNA 吸附和解吸附（利用DNA 杂交）在纳米金表面的化学反应调控纳米金组装线的电学信号转换，从而实现对DNA的超高灵敏和超低检测下限的检测功能，并在此基础上发展阵列纳米器件。这对发展高灵敏度、高通量、低检测下限、快速、操作简便的检测和筛选单核苷酸多态性的DNA 生物传感技术具有重要意义。

提高DNA检测灵敏度与检测下限对DNA检测技术具有重要意义。本项目发展了基于碳纳米管/纳米金DNA检测新技术。在可控生长单壁碳纳米管基础上，以碳纳米管作为金属纳米金生长的载体，通过构建基于EBL工艺制备的微小型狭缝器件及对狭缝距离的调控，使狭缝间金颗粒生长连通电极后，电极间电导变化更为明显。通过对不同狭缝间距器件的检测效果进行对比，对于同种浓度的DNA样品，狭缝越小灵敏度越高；对于不同浓度的DNA样品，越小狭缝的器件能获取更大的检测范围和更低的检测下限。 当狭缝距离达到250纳米时，可以测出1 pM的最低检测下限。本项目为开发高灵敏度低检测下限的DNA传感器打下基础。