scholarly journals Trapping solid aerosols with optical tweezers: A comparison between gas and liquid phase optical traps

2008 ◽  
Vol 16 (11) ◽  
pp. 7739 ◽  
Author(s):  
M. D. Summers ◽  
D. R. Burnham ◽  
D. McGloin
Keyword(s):  
Liquid Phase ◽  
Optical Tweezers ◽  
Optical Traps

scholarly journals Bio-Molecular Applications of Recent Developments in Optical Tweezers

Biomolecules ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 23 ◽  
Author(s):  
Dhawal Choudhary ◽  
Alessandro Mossa ◽  
Milind Jadhav ◽  
Ciro Cecconi
Keyword(s):  
Photonic Crystal ◽  
Optical Tweezers ◽  
Single Molecule ◽  
Continuous Wave ◽  
Imaging Techniques ◽  
Resolving Power ◽  
Optical Traps ◽  
Laser Source ◽  
One Dimensional

In the past three decades, the ability to optically manipulate biomolecules has spurred a new era of medical and biophysical research. Optical tweezers (OT) have enabled experimenters to trap, sort, and probe cells, as well as discern the structural dynamics of proteins and nucleic acids at single molecule level. The steady improvement in OT’s resolving power has progressively pushed the envelope of their applications; there are, however, some inherent limitations that are prompting researchers to look for alternatives to the conventional techniques. To begin with, OT are restricted by their one-dimensional approach, which makes it difficult to conjure an exhaustive three-dimensional picture of biological systems. The high-intensity trapping laser can damage biological samples, a fact that restricts the feasibility of in vivo applications. Finally, direct manipulation of biological matter at nanometer scale remains a significant challenge for conventional OT. A significant amount of literature has been dedicated in the last 10 years to address the aforementioned shortcomings. Innovations in laser technology and advances in various other spheres of applied physics have been capitalized upon to evolve the next generation OT systems. In this review, we elucidate a few of these developments, with particular focus on their biological applications. The manipulation of nanoscopic objects has been achieved by means of plasmonic optical tweezers (POT), which utilize localized surface plasmons to generate optical traps with enhanced trapping potential, and photonic crystal optical tweezers (PhC OT), which attain the same goal by employing different photonic crystal geometries. Femtosecond optical tweezers (fs OT), constructed by replacing the continuous wave (cw) laser source with a femtosecond laser, promise to greatly reduce the damage to living samples. Finally, one way to transcend the one-dimensional nature of the data gained by OT is to couple them to the other large family of single molecule tools, i.e., fluorescence-based imaging techniques. We discuss the distinct advantages of the aforementioned techniques as well as the alternative experimental perspective they provide in comparison to conventional OT.

COUNTING UNFOLDING EVENTS IN STRETCHED HELICES WITH INDUCED OSCILLATION BY OPTICAL TWEEZERS

2012 ◽  
Vol 17 ◽  
pp. 44-53
Author(s):  
ROMMEL GAUD BACABAC ◽  
ROLAND OTADOY
Keyword(s):  
Optical Tweezers ◽  
Viscoelastic Properties ◽  
Globular Proteins ◽  
Optical Traps ◽  
Living Matter ◽  
Damped Harmonic Oscillator ◽  
Catch Up ◽  
Correlation Measures ◽  
Complex Phenomena ◽  
First Time

Correlation measures based on embedded probe fluctuations, single or paired, are now widely used for characterizing the viscoelastic properties of biological samples. However, more robust applications using this technique are still lacking. Considering that the study of living matter routinely demonstrates new and complex phenomena, mathematical and experimental tools for analysis have to catch up in order to arrive at newer insights. Therefore, we derive ways of probing non-equilibrium events in helical biopolymers provided by stretching beyond thermal forces. We generalize, for the first time, calculations for winding turn probabilities to account for unfolding events in single fibrous biopolymers and globular proteins under tensile stretching using twin optical traps. The approach is based on approximating the ensuing probe fluctuations as originating from a damped harmonic oscillator under oscillatory forcing.

Optically driven pumps and flow sensors for microfluidic systems

2008 ◽  
Vol 222 (5) ◽  
pp. 829-837 ◽  
Author(s):  
H Mushfique ◽  
J Leach ◽  
R Di Leonardo ◽  
M J Padgett ◽  
J M Cooper
Keyword(s):  
Fluid Flow ◽  
Optical Tweezers ◽  
Microfluidic Channel ◽  
Optical Traps ◽  
Spin Angular Momentum ◽  
Flow Sensors ◽  
Flow Sensing ◽  
Optically Trapped ◽  
Surrounding Fluid ◽  
Displace Fluid

This paper describes techniques for generating and measuring fluid flow in microfluidic devices. The first technique is for the multi-point measurement of fluid flow in microscopic geometries. The flow sensing method uses an array of optically trapped microprobe sensors to map out the fluid flow. The optical traps are alternately turned on and off such that the probe particles are displaced by the flow of the surrounding fluid and then retrapped. The particles' displacements are monitored by digital video microscopy and directly converted into velocity field values. The second is a method for generating flow within a microfluidic channel using an optically driven pump. The optically driven pump consists of two counter-rotating birefringent vaterite particles trapped within a microfluidic channel and driven using optical tweezers. The transfer of spin angular momentum from a circularly polarized laser beam causes the particles to rotate at up to 10 Hz. The pump is shown to be able to displace fluid in microchannels, with flow rates of up to 200 m−3 s−1 (200 fL s−1). In addition a flow sensing method, based upon the technique mentioned above, is incorporated into the system in order to map the magnitude and direction of fluid flow within the channel.

scholarly journals Microrheology With an Anisotropic Optical Trap

2021 ◽  
Vol 9 ◽  
Author(s):  
Andrew B. Matheson ◽  
Tania Mendonca ◽  
Graham M. Gibson ◽  
Paul A. Dalgarno ◽  
Amanda J. Wright ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Optical Trap ◽  
Threshold Level ◽  
Optical Traps ◽  
Elliptical Cross ◽  
Maximum Variance ◽  
The Difference ◽  
Axes Of Symmetry ◽  
Spurious Results ◽  
Arbitrary Axis

Microrheology with optical tweezers (MOT) measurements are usually performed using optical traps that are close to isotropic across the plane being imaged, but little is known about what happens when this is not the case. In this work, we investigate the effect of anisotropic optical traps on microrheology measurements. This is an interesting problem from a fundamental physics perspective, but it also has practical ramifications because in 3D all optical traps are anisotropic due to the difference in the intensity distribution of the trapping laser along axes parallel and perpendicular to the direction of beam propagation. We find that attempting viscosity measurements with highly anisotropic optical traps will return spurious results, unless the axis with maximum variance in bead position is identified. However, for anisotropic traps with two axes of symmetry such as traps with an elliptical cross section, the analytical approach introduced in this work allows us to explore a wider range of time scales than those accessible with symmetric traps. We have also identified a threshold level of anisotropy in optical trap strength of ~30%, below which conventional methods using a single arbitrary axis can still be used to extract valuable microrheological results. We envisage that the outcomes of this study will have important practical ramifications on how all MOT measurements should be conducted and analyzed in future applications.

Complex Three-Dimensional Fluidic Reservoirs to Control Beads/Living Cells Contacts

2006 ◽  
Author(s):  
Serge Monneret ◽  
Federico Belloni ◽  
Olivier Soppera
Keyword(s):  
Optical Tweezers ◽  
Target Cell ◽  
Three Dimensional ◽  
Microfluidic System ◽  
Optical Traps ◽  
Multiple Point ◽  
Point Interactions ◽  
Cover Glass ◽  
Holographic Optical Tweezers ◽  
Microscope Cover Glass

In this paper, we combine holographic multiple optical tweezers with a three-dimensional microfluidic system to create a versatile microlaboratory. In order to determine cells local and/or temporal response to stimuli, and therefore draw their map of sensitivity, one convenient way is to apply antigen-covered latex beads in order to bind to plasma membrane, by means of optical tweezers. Using multiple optical traps could improve the efficiency of the measurements, but also their versatility. Therefore, we have developed a complete system based on holographic optical tweezers to realise multiple-point interactions between beads and cells with control of the stimulation places, timing, and durations. As we plan to use our system to study biological events in the hour timescale, we have to keep beads and cells separated, in order to prevent unwanted beads to circulate freely in the sample and bind to the target cell during the experiment. We then introduced microstereolithography as a 3D micro-manufacturing approach to the rapid prototyping of three-dimensional fluidic microchambers of complex shapes inside the sample, comprising wells, channels and walls to inject beads locally and keep them separated from cells in our assays. We demonstrated the possibility for microSL to easily and rapidly (typically one hour) fabricate small and three-dimensional observation chambers with customized design of the flow channels, including fluidic reservoirs of typically 500–1500 μm diameter, 5–12 mm height, in order to facilitate manual filling. Several shapes of reservoirs designed to keep beads and cells separated in liquid samples have been realized and successfully tested. Some of them included up to 3 reservoirs, in order to allow co-distribution of different types of beads. Each reservoir typically contained 2–10 μl of solution holding the beads, with a horizontal outlet of 100–200 μm in diameter which allows beads to deposit locally on the microscope cover glass placed under the reservoir outlet. Limited extension of beads under the outlet on the glass has been confirmed, and the ability of the polymeric structures to confine beads in a restricted area has been demonstrated. In the following we present examples of manipulations by multiple holographic optical tweezers consisting at first in extracting several beads from such an area by going through an aperture designed in the structure, making them travel to the target cell, and finally depositing on its outer membrane.

Using GPUs for Realtime Prediction of Optical Forces on Microsphere Ensembles

2012 ◽  
Author(s):  
Sujal Bista ◽  
Sagar Chowdhury ◽  
Satyandra K. Gupta ◽  
Amitabh Varshney
Keyword(s):  
Laser Beam ◽  
Optical Tweezers ◽  
Computational Models ◽  
Laser Beams ◽  
Cell Manipulation ◽  
Optical Traps ◽  
Optical Forces ◽  
Gaussian Laser Beam ◽  
Multiple Particles ◽  
Speed Up

Laser beams can be used to create optical traps that can hold and transport small particles. Optical trapping has been used in a number of applications ranging from prototyping at the microscale to biological cell manipulation. Successfully using optical tweezers requires predicting optical forces on the particle being trapped and transported. Reasonably accurate theory and computational models exist for predicting optical forces on a single particle in the close vicinity of a Gaussian laser beam. However, in practice the workspace includes multiple particles that are manipulated using individual optical traps. It has been experimentally shown that the presence of a particle can cast a shadow on a nearby particle and hence affect the optical forces acting on it. Computing optical forces in the presence of shadows in real-time is not feasible on CPUs. In this paper, we introduce a ray-tracing-based application optimized for GPUs to calculate forces exerted by the laser beams on microparticle ensembles in an optical tweezers system. When evaluating the force exerted by a laser beam on 32 interacting particles, our GPU-based application is able to get a 66-fold speed up compared to a single core CPU implementation of traditional Ashkin’s approach and a 10-fold speedup over its single core CPU-based counterpart.

scholarly journals Axial Optical Traps: A New Direction for Optical Tweezers

2015 ◽  
Vol 108 (12) ◽  
pp. 2759-2766 ◽  
Author(s):  
Samuel Yehoshua ◽  
Russell Pollari ◽  
Joshua N. Milstein
Keyword(s):  
Optical Tweezers ◽  
Optical Traps

scholarly journals Reliable and mobile all-fiber modular optical tweezers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chaoyang Ti ◽  
Yao Shen ◽  
Minh-Tri Ho Thanh ◽  
Qi Wen ◽  
Yuxiang Liu
Keyword(s):  
Optical Tweezers ◽  
Optical Fibers ◽  
Point Of Care ◽  
Optical Trap ◽  
Optical Traps ◽  
Modular System ◽  
Breast Epithelial Cell ◽  
Epithelial Cell Line ◽  
Position Detection ◽  
Breast Epithelial Cell Line

AbstractMiniaturization and integration of optical tweezers are attractive. Optical fiber-based trapping systems allow optical traps to be realized in miniature systems, but the optical traps in these systems lack reliability or mobility. Here, we present the all-fiber modular optical tweezers (AFMOTs), in which an optical trap can be reliably created and freely moved on a sample substrate. Two inclined optical fibers are permanently fixed to a common board, rendering a modular system where fiber alignments are maintained over months. The freely movable optical trap allows particles to be trapped in their native locations. As a demonstration, we applied AFMOTs to trap and deform freely floating individual cells. By the cell mechanical responses, we differentiated the nontumorigenic breast epithelial cell line (MCF10A) from its cancerous PTEN mutants (MCF10 PTEN-/-). To further expand the functionalities, three modalities of AFMOTs are demonstrated by changing the types of fibers for both the optical trap creation and particle position detection. As a miniature and modular system that creates a reliable and mobile optical trap, AFMOTs can find potential applications ranging from point-of-care diagnostics to education, as well as helping transition the optical trapping technology from the research lab to the field.

scholarly journals Tele–Robotic Platform for Dexterous Optical Single-Cell Manipulation

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 677 ◽  
Author(s):  
Edison Gerena ◽  
Florent Legendre ◽  
Akshay Molawade ◽  
Youen Vitry ◽  
Stéphane Régnier ◽  
...  
Keyword(s):  
Single Cell ◽  
Optical Tweezers ◽  
Biomedical Applications ◽  
High Speed ◽  
Cell Manipulation ◽  
Optical Traps ◽  
A Cell ◽  
Six Dof ◽  
Master Device ◽  
Single Cell Manipulation

Single-cell manipulation is considered a key technology in biomedical research. However, the lack of intuitive and effective systems makes this technology less accessible. We propose a new tele–robotic solution for dexterous cell manipulation through optical tweezers. A slave-device consists of a combination of robot-assisted stages and a high-speed multi-trap technique. It allows for the manipulation of more than 15 optical traps in a large workspace with nanometric resolution. A master-device (6+1 degree of freedom (DoF)) is employed to control the 3D position of optical traps in different arrangements for specific purposes. Precision and efficiency studies are carried out with trajectory control tasks. Three state-of-the-art experiments were performed to verify the efficiency of the proposed platform. First, the reliable 3D rotation of a cell is demonstrated. Secondly, a six-DoF teleoperated optical-robot is used to transport a cluster of cells. Finally, a single-cell is dexterously manipulated through an optical-robot with a fork end-effector. Results illustrate the capability to perform complex tasks in efficient and intuitive ways, opening possibilities for new biomedical applications.

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