Torsional Stiffness of Single Superparamagnetic Microspheres in an External Magnetic Field

被引：85

作者：

Klaue, Daniel ^{[1
]}

Seidel, Ralf ^{[1
]}

机构：

[1] Tech Univ Dresden, DNA Motors Grp, Ctr Biotechnol, D-01062 Dresden, Germany

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 102卷 / 02期

关键词：

OPTICAL TWEEZERS; SUPERCOILED DNA; MOLECULE; BEHAVIOR; FORCES;

D O I：

10.1103/PhysRevLett.102.028302

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We used magnetic tweezers to measure the torsional stiffness of single micrometer-sized superparamagnetic spheres as a function of the applied magnetic field. By investigating the axial fluctuations of DNA-bound microspheres, we found that considerable rotational microsphere fluctuations can occur. Quantitative noise analysis allowed us to determine the rotational stiffness of individual microspheres, which was found to saturate at high magnetic fields. The saturation can be qualitatively explained considering the properties of the magnetic nanoparticles within the microsphere. Consequences for spatial resolution limits in single-molecule magnetic tweezer experiments and usage of DNA mechanics as a sensitive probe in magnetometry are discussed.

引用

页数：4

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