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Optical Tweezers for Manipulation of Single Molecules
Published in Shuo Huang, Single-Molecule Tools for Bioanalysis, 2022
Optical tweezers were immediately found to be useful in biological research, due to their ability to trap and move microorganisms without physical contact, which can even allow manipulation of organelles in live cells [9]. In addition, the ability to measure small forces, from femtonewtons to some tens of piconewtons, has made optical tweezers a star player in quantitative biophysics and mechanobiology [10]. In this chapter, our aim is to provide a comprehensive overview of optical trapping theory, and considerations for instrument design and calibration which helps biophysicists, biochemists, and cell biologists to build and calibrate their own instruments and to perform single-molecule force measurements on both in vitro systems and in living cells. Finally, we will attempt to communicate our sense of future directions for this growing field.
Optical Tweezers
Published in Yubing Xie, The Nanobiotechnology Handbook, 2012
Yingbo Zu, Fangfang Ren, Shengnian Wang
The basic use of optical tweezers in cell related research is to trap cells and position them at desired locations. As such, grabbing and relocating does not require contact with a solid surface or other cells, it is convenient to create appropriate model systems for some fundamental studies. For example, a single kidney cell was optically trapped to reveal the water transport across the cell membrane and correspondingly the volume change dynamics under osmotic shock (Lucio et al. 2003). Single K562 cells (a chronic leukemia cell line) had been positioned at various locations between two electrodes to study the cell membrane permeability change during and after an electric pulse to help understand the cell electroporation mechanism (Figure 19.8).
Optical Tweezers
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Optical tweezers has been rapidly developed to manipulate various objects, including biological cells and particles. Moreover, optical forces produced by commonly available lasers lie in the piconewton range, which is just right to handle experiments with individual molecules. In addition, as most biological materials absorb only weakly in the near IR region of the electromagnetic spectrum, Nd:YAG (λ = 1,064 nm) lasers are well suited to optical tweezers applications in biology. Because of the diffraction limit, the resolution of conventional optical microscopes (∼200 nm) is too low for observing single protein molecules, even their small assembly. Therefore, researchers have developed a variety of techniques and methodologies that enable indirect access to these mechanical parameters, allowing for a more comprehensive understanding of the behavior of certain biological components. Especially, the magnitude of optical forces in optical tweezers system is generally insufficient to stably trap biological macromolecules themselves but more than adequate for manipulating microscopic dielectric objects, such as polystyrene spheres or silica particles, which can be utilized as carriers or handles to be biochemically linked to these molecules. To date, the greatest remarkable progress of optical tweezers is to revolutionize biology by investigating the mechanical properties of a single molecule [36,37]. This technology has revealed important information about molecular structures and mechanisms, and their biggest impact has been in studies of molecular motors that convert chemical potential energy into mechanical work. It opens up new fields in the biological and biophysical sciences to understand how the components of life behave, not only biochemically but also mechanically.
Generation and control of multiple optical bottles from chirped Airy–Gaussian vortex beams: theory and experiment
Published in Waves in Random and Complex Media, 2022
Shangling He, Yong Zhang, Boris A. Malomed, Dumitru Mihalache, Liping Zhang, Sijing Zhang, Qiaobin Huang, Huixin Qiu, Jiajia Zhao, Xi Peng, Yingji He, Dongmei Deng
Optical tweezers, which are often built on the basis of Airy beams and OVs, have been used since long ago to transfer or manipulate particles, to study soft matter, and so on. Using the force generated by the strongly focused beam, optical tweezers can capture and move microscopic objects [38]. In particular, they find profoundly important applications in microbiology and medicine [39, 40]. Recently, the creation of optical-bottle (OB) beams has been reported, enabling the capture of multiple particles [41]. Then, a close dark focus was formed and surrounded by uniform light intensity in all directions of the OB beams [42, 43]. OBs were designed by means of various methods, such as the self-image effect [44], Fourier-space generation [26], etc. Lately, a variety of beams in the free space which are capable to generate the ‘bottles’ have been reported, including chirped ring-shaped Pearcey-Gaussian vortex beams [45], second-order chirped symmetric Airy vortices [46], chirped ring symmetric Airy beams carrying spectral OVs [47], and others.
Sorting of micron-sized particles using holographic optical Raman tweezers in aqueous medium
Published in Journal of Modern Optics, 2019
Uğur Parlatan, Gönül Başar, Günay Başar
The dynamical effect of radiation pressure, which was well proved theoretically and experimentally in the early 1900s (1-3), had let Arthur Ashkin discover new possibilities for the manipulation of micron-sized particles which he called ‘Optical Tweezers’ (4, 5). Optical tweezers had quickly become a useful and accessible tool in several disciplines especially in biology and medical sciences. Besides the non-invasive nature of it, the ability of this method to easily be combined with measurement techniques, such as spectroscopy, makes optical tweezers useful for the many kinds of applications using single biological cells. Cell viability [6], force measurement of motor molecules (6), investigation of microorganisms (7), cell division (8), cell signalling (9), observation of cells in disease states and determination of chemical components differing (10, 11) are some examples for these measurements.