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Updated: Feb 2, 2026

Single-molecule Manipulation of G-quadruplexes by Magnetic Tweezers
Published on: September 19, 2017
A Horizontal Magnetic Tweezers and Its Use for Studying Single DNA Molecules
Roberto Fabian1, Christopher Tyson2, Pamela L Tuma3
1Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA. 76fabian@cua.edu.
Abstract:
We report the development of a magnetic tweezers that can be used to micromanipulate single DNA molecules by applying picoNewton (pN)-scale forces in the horizontal plane. The resulting force⁻extension data from our experiments show high-resolution detection of changes in the DNA tether's extension: ~0.5 pN in the force and <10 nm change in extension. We calibrate our instrument using multiple orthogonal techniques including the well-characterized DNA overstretching transition. We also quantify the repeatability of force and extension measurements, and present data on the behavior of the overstretching transition under varying salt conditions. The design and experimental protocols are described in detail, which should enable straightforward reproduction of the tweezers.
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