DNA原子力显微镜成象方法研究  

STUDY ON THE DNA IMAGING METHOD OF ATOMIC FORCE MICROSCOPE

作　　者：汪新文[1] 白春礼[1] 朱传风[1] 

机构地区：[1]中国科学院化学研究所

出　　处：《生物物理学报》1996年第3期538-543,共6页Acta Biophysica Sinica

基　　金：中国科学院"八.五"重大科研项目;国家自然科学基金

摘　　要：采用Ｓｅｐｈａｄｅｘ色谱柱分离，保温稀释的ＤＮＡ溶液，不仅可除去ＤＮＡ链上吸附的盐，而且可使盘绕一起的ＤＮＡ链部分展开；在此基础上，通过采用苯二甲基辛基溴化胺（ＢＡＢ）－甲酰胺微量展层技术，可使纳克级ＤＮＡ完全展开到云母基底上。通过无菌水和无水乙醇洗涤样品表面，不仅可除去杂质颗粒，而且可使展开的ＤＮＡ链有效地固定到基底上。实验结果表明，通过以上较为系统的样品制备方法，可获得满足原子力显微镜（ＡＦＭ）成象的ＤＮＡ样品，并且再现性好。我们比较了不同环境，例如空气、正丁醇、无水乙醇、９５％乙醇和水，ＡＦＭ成象ＤＮＡ样品时的力曲线，发现ＡＦＭ针尖和ＤＮＡ间的相互作用力不同，成象分辨率亦受到影响。Using Sephadex gel filtration and incubating λ-DNA Hind Ⅲ solution at 36℃, thesamples could be purified from salt on strand with partially extended DNA for AFMobservation. Moreover, the protein-free spreading-free spreading technique, involvingbenzyldimethyl-alkyammonium bromide (BAB) and the denaturing agent formamide, wasestablished. With very low DNA concentration, the fully extended DNA samples for linearDNA can be prepared. Washing the samples in alcohol a few times, the DNA fragments cantightly adsorb on the mica substrate. Depending on above processes, we can get thereproducible sampleS for haging with high resolution AFM. comparing the AFM forcecalibration plots in different imaging condition,such as air, butyl alcohol, alcohol, 95% alcoholand water, the effect on the haging resolution caused by force differences AFM tipand sample surface was also discussed.

关 键 词：DNA 原子力显微镜 成像 

分 类 号：Q523.02[生物学—生物化学]