利用AFM探针施加的正偏压提高单个DNA分子的分离效率

第 2期 张 琛等：利用 AFM探针施加的正偏压提高单个 DNA分子的分离效率 143lmDroving lS0laU0n 1r J efi ciency of single DNAfr，gments by positively biased AFM tipta D D ZHANG Chen ，ZHANG Fu-chun ，YANG Hai-jun ，SHEN Yue -，ZHANG Yi ，HU Jun(1.Shanghai Institute of Applied Phyisics，Chineses Academy of Sciences，Laboratory of Physical Biology，Shanghai 2018002.University of Chinese Academy of Sciences，Beijing 1 00049；3.Shanghai Jiaotong University，Research Institute of Micro/Nano Science and Technology，Shanghai 200240，China)Abstract：The atomic force microscope(AFM)can image and manipulate native biological samples on surfaces on the single-moleculelevel，including cuting，pushing and picking-up.By applying a positive bias to AFM tip，we have developed a new method for DNAisolation(picking-up)from chemicaly-modifed mica surface.The positive bias on the AFM tip produces electrostatic atraction forcebetween the negatively charged DNA molecules and the tip，which increases DNA picking-up eficiency.By single-molecule PCR，thepicked-up DNA can be successfuly amplifed，indicating the DNA molecules keep their biological activities after the manipulation bythe biased AFM tip。

Keywords：AFM；DNA isolation(picking-up)；positive bias；electrostatic attraction force Corresponding author