An optical apparatus for rotation and trapping.

Methods in Enzymology
Braulio Gutiérrez-MedinaSteven M Block

Abstract

We present details of the design, construction, and testing of a single-beam optical tweezers apparatus capable of measuring and exerting torque, as well as force, on microfabricated, optically anisotropic particles (an "optical torque wrench"). The control of angular orientation is achieved by rotating the linear polarization of a trapping laser with an electro-optic modulator (EOM), which affords improved performance over previous designs. The torque imparted to the trapped particle is assessed by measuring the difference between left- and right-circular components of the transmitted light, and constant torque is maintained by feeding this difference signal back into a custom-designed electronic servo loop. The limited angular range of the EOM (+/-180 degrees ) is extended by rapidly reversing the polarization once a threshold angle is reached, enabling the torque clamp to function over unlimited, continuous rotations at high bandwidth. In addition, we developed particles suitable for rotation in this apparatus using microfabrication techniques. Altogether, the system allows for the simultaneous application of forces (approximately 0.1-100 pN) and torques (approximately 1-10,000 pN nm) in the study of biomolecules. As a proof...Continue Reading

Citations

Apr 5, 2011·The Review of Scientific Instruments·Francesco MosconiVincent Croquette
Apr 2, 2013·Annual Review of Biophysics·Scott ForthMichelle D Wang
Sep 2, 2014·Integrative Biology : Quantitative Biosciences From Nano to Macro·J Ricardo Arias-Gonzalez
Jun 17, 2014·Lab on a Chip·Prateek BenhalWenhui Wang
Mar 2, 2013·PloS One·Carmen Noemí Hernández CandiaBraulio Gutiérrez-Medina
May 15, 2015·Optics Express·Oto BrzobohatýPavel Zemánek
Mar 13, 2019·Scientific Reports·Alejandro V ArzolaPavel Zemánek
Mar 16, 2012·Optics Express·Francesco PedaciNynke H Dekker
Sep 3, 2020·The Review of Scientific Instruments·Akio KawasakiGiorgio Gratta
Feb 5, 2021·Biomicrofluidics·Liang HuangWenhui Wang
May 6, 2020·Nano Letters·Rudy DesgarceauxFrancesco Pedaci
Dec 30, 2014·Chemical Reviews·Jan LipfertNynke H Dekker
Feb 2, 2011·ACS Nano·Zhuangxiong HuangNynke H Dekker

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