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A review of magnetic tweezers applied to biological molecules
Joseph Duke
University of Kentucky
March 2nd 2016, 12:00pm CP-114B
Measurement and control of force upon biological systems reveals many insights into function. [1] Magnetic tweezers use magnetic force to manipulate sample molecules with magnetic attachments. [1] [2] The advantages of magnetic tweezers over similar aiming techniques include high upper bounds to applied force, ability to adjust sample torque, and insensitivity of biological samples to magnetism. [1] [2] Both permanent magnets and electromagnets can be used to apply force upon magnetic beads attached to sample molecules. [1] Extension of samples is often measured through a microscope functionalized camera visualizing interference patterns of light scattered off the magnetic bead tether. [1] [2] Careful calibration of both position and force is necessary for accurate data collection. [1] Through measurement and adjustment of applied force and torque, the effects of DNA interacting agents upon extension and twist of DNA was explored by Salerno et. Al. (2010) [3] While magnetic tweezers strengths lend them well to DNA studies, the technique has proven to be useful in the study of other biological systems. [1] Shang and Lee (2007) developed an experimental setup able to probe large sample sizes with the intent of investigating the modes of protein A binding to IgG. [4] As the technology and materials necessary for this technique have advanced, so have the capabilities of this technique. [4] Magnetic tweezers are an effective technique in force studies rooted in single molecule spectroscopy, with advancements allowing for arrays of samples. [1] [4] The technique is well suited for a diverse set of biological applications, and has potential in answering many scientific questions.
References:
1. Neuman, K.C.; Nagy, A. Single-molecule force spectroscopy: optical tweezers, magnetic tweezers and atomic force microscopy. Nat Methods. 2008, 5, 491-505.
2. Vilfan, I.D.; Lipfert, J.; Koster, D.A.; Lemay, S.G.; Dekker, N.H.; Magnetic Tweezers for Single-Molecule Experiments. In Handbook of Single-Molecule Biophysics. Hinterdorfer, P., can Oijen, A., Eds.; Springer Science+Business Media: New York, 2009; pp. 371-395.
3. Salerno, D.; Brogioli, D.; Cassina, V.; Turchi, D.; Beretta, G.L.; Seruggia, D.; Ziano R.; Zunino, F.; Mantegazza, F.; Magnetic tweezers measurements of the nanomechanical properties of DNA in the presence of drugs. Nucleic Acids Research. 2010, 38, 7089- 7099.
4. Shang, H.; Lee, G.U.; Magnetic tweezers measurement of the bond lifetime-force behavior of the IgG-protein A specific molecular interaction. J. Am. Chem. Soc. 2007, 129, 6640-6646.
Course Instructor: Dr. Jason DeRouchey
