A simple and effective sample preparation method for atomic force microscopy visualization of individual DNA molecules in situ.
A simple, controllable and effective sample preparation method was established for atomic force microscopy (AFM) imaging of individual DNA molecules in aqueous solution. Firstly, magnesium ion (Mg(2+)) at a concentration of 5.0-10.0 mM as a positively charged bridge was transferred onto mica to immobilize DNA molecules. Then Mg(2+)-modified mica was used to investigate DNA molecules in any buffer without magnesium ion by AFM. AFM images demonstrated that DNA molecules can be successfully observed in solution with good resolution, reproducibility, and stability. Further, this DNA sample preparation method makes AFM successful to investigate DNA molecular interaction in situ and DNA/chitosan complex in gene delivery.
National Engineering Research Center for Nanotechnology, Shanghai, 200241, China.
Xin-Cheng
XC
Shen
Lei
L
Bao
Zhi-Ling
ZL
Zhang
Xiaoshen
X
Liu
Dai-Wen
DW
Pang
Jianrong
J
Xu
D002021:Buffers; D048271:Chitosan / Q000737:chemistry; D004247:DNA / Q000235:genetics* / Q000648:ultrastructure; D018014:Gene Transfer Techniques; D008274:Magnesium / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D008967:Molecular Biology / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis
D002021:Buffers; D004247:DNA; D048271:Chitosan; D008274:Magnesium