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Sci Rep ; 9(1): 8889, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31222124


Low-energy electrons offer a unique possibility for long exposure imaging of individual biomolecules without significant radiation damage. In addition, low-energy electrons exhibit high sensitivity to local potentials and thus can be employed for imaging charges as small as a fraction of one elementary charge. The combination of these properties makes low-energy electrons an exciting tool for imaging charge transport in individual biomolecules. Here we demonstrate the imaging of individual deoxyribonucleic acid (DNA) molecules at the resolution of about 1 nm with simultaneous imaging of the charging of the DNA molecules that is of the order of less than one elementary charge per nanometer. The cross-correlation analysis performed on different sections of the DNA network reveals that the charge redistribution between the two regions is correlated. Thus, low-energy electron microscopy is capable to provide simultaneous imaging of macromolecular structure and its charge distribution which can be beneficial for imaging and constructing nano-bio-sensors.

PLoS One ; 8(7): e69058, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23935923


We present "molecular threading", a surface independent tip-based method for stretching and depositing single and double-stranded DNA molecules. DNA is stretched into air at a liquid-air interface, and can be subsequently deposited onto a dry substrate isolated from solution. The design of an apparatus used for molecular threading is presented, and fluorescence and electron microscopies are used to characterize the angular distribution, straightness, and reproducibility of stretched DNA deposited in arrays onto elastomeric surfaces and thin membranes. Molecular threading demonstrates high straightness and uniformity over length scales from nanometers to micrometers, and represents an alternative to existing DNA deposition and linearization methods. These results point towards scalable and high-throughput precision manipulation of single-molecule polymers.

Ar , DNA/química , Conformação de Ácido Nucleico , Soluções/química , DNA/ultraestrutura , DNA de Cadeia Simples/química , DNA de Cadeia Simples/ultraestrutura , Microscopia Eletrônica/métodos , Microscopia de Fluorescência/métodos , Reprodutibilidade dos Testes , Propriedades de Superfície , Tecnologia/instrumentação , Tecnologia/métodos