Effects of Bridge Ions, DNA Species, and Developing Temperature on Flat-Lying DNA Monolayers
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- 作者：Yonghai Song ; Cunlan Guo ; Lanlan Sun ; Gang Wei ; Chongyang Peng ; Li Wang ; Yujing Sun ; Zhuang Li
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：January 18, 2007
- 年：2007
- 卷：111
- 期：2
- 页码：461 - 468
- 全文大小：1595K
- 年卷期：v.111,no.2(January 18, 2007)
- ISSN：1520-5207
文摘
Recently, we have successfully constructed flat-lying DNA monolayers on a mica surface (J. Phys. Chem. B2006, 110, 10792-10798). In this work, the effects of various factors including bridge ions, DNA species,and developing temperature on the configuration of DNA monolayers have been investigated by atomic forcemicroscopy (AFM) in detail. AFM results show that the species of bridge ions and developing temperatureplay a crucial role during the formation process. For example, the divalent cation Zn2+ resulted in manyDNA chains stuck side by side in the monolayers due to the strong interactions between it and DNA's basesor the mica surface. Most DNA chain's conglutinations disappeared when the developing temperature washigher than 40 
C. Cd2+ and Ca2+ produced more compact DNA monolayers with some obvious aggregations,especially for the DNA monolayers constructed by using Ca2+ as the bridge ion. Co2+ produced well-ordered,flat-lying DNA monolayers similar to that of Mg2+. Furthermore, it was found that the flat-lying DNAmonolayers could still form on a mica surface when plasmid DNA pBR 322 and linear DNA pBR 322/PstI were used as the DNA source. Whereas, it was hard to form DNA monolayers on a (3-aminopropyl)triethoxysilane-mica surface because the strong interactions between DNA and substrate prevented the lateralmovement of DNA molecules. These results suggested that the appropriate interactions between divalentcations and DNA or mica surface were important for the formation of flat-lying DNA monolayers. The obtainedinformation is a necessary supplement to our previous studies on the formation kinetics of such monolayersand may be useful for practical application of the monolayers and further theoretical studies.
C. Cd2+ and Ca2+ produced more compact DNA monolayers with some obvious aggregations,especially for the DNA monolayers constructed by using Ca2+ as the bridge ion. Co2+ produced well-ordered,flat-lying DNA monolayers similar to that of Mg2+. Furthermore, it was found that the flat-lying DNAmonolayers could still form on a mica surface when plasmid DNA pBR 322 and linear DNA pBR 322/PstI were used as the DNA source. Whereas, it was hard to form DNA monolayers on a (3-aminopropyl)triethoxysilane-mica surface because the strong interactions between DNA and substrate prevented the lateralmovement of DNA molecules. These results suggested that the appropriate interactions between divalentcations and DNA or mica surface were important for the formation of flat-lying DNA monolayers. The obtainedinformation is a necessary supplement to our previous studies on the formation kinetics of such monolayersand may be useful for practical application of the monolayers and further theoretical studies.