Enhancing Range of Transport in Optical Tweezers Assisted Microfluidic Chambers Using Automated Stage Motion

2013 ◽  
Author(s):  
Sagar Chowdhury ◽  
Petr Švec ◽  
Atul Thakur ◽  
Chenlu Wang ◽  
Wolfgang Losert ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
High Speed ◽  
Optical Trap ◽  
Heuristic Method ◽  
Optical Traps ◽  
Greedy Heuristic ◽  
Long Distance ◽  
Microfluidic Chamber ◽  
Planning Approach ◽  
Cell Ensemble

In this paper, we present a planning approach for automated high-speed transport of cells over large distances inside an Optical Tweezers (OT) assisted microfluidic chamber. The transport is performed in three steps that combine the optical trap and motorized stage motions. This includes optical trapping and transporting the cells to form a desired cell-ensemble that is suitable for a long distance transport, automatically moving the motorized stage to transport the cell-ensemble over a large distance while avoiding static obstacles, and distributing the cells from the ensemble to the desired locations using OT. The speeds of optical traps and the motorized stage are determined by modeling the motion of the particle under the influence of optical trap. The desired cell-ensemble is automatically determined based on the geometry of the microfluidic chamber. We have developed a greedy heuristic method for optimal selection of the initial and the final location of the cell-ensemble to minimize the overall transport time while satisfying the constraints of the OT workspace. We have discussed the computational complexity of the developed method and compared it with exhaustive combinatorial search. The approach is particularly useful in applications where cells are needed to be rapidly distributed inside a microfluidic chamber. We show the capability of our planning approach using physical experiments.

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.

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.

scholarly journals Generation of Hybrid Optical Trap Array by Holographic Optical Tweezers

2021 ◽  
Vol 9 ◽  
Author(s):  
Xing Li ◽  
Yuan Zhou ◽  
Yanan Cai ◽  
Yanan Zhang ◽  
Shaohui Yan ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Optical Trap ◽  
Optical Traps ◽  
Axial Position ◽  
Spatial Light Modulators ◽  
Light Modulators ◽  
Multiple Particles ◽  
Holographic Optical Tweezers ◽  
Almost All ◽  
Gaussian Point

Enabled by multiple optical traps, holographic optical tweezers can manipulate multiple particles in parallel flexibly. Spatial light modulators are widely used in holographic optical tweezers, in which Gaussian point (GP) trap arrays or special mode optical trap arrays including optical vortex (OV) arrays, perfect vortex (PV) arrays, and Airy beam arrays, etc., can be generated by addressing various phase holograms. However, the optical traps in these arrays are almost all of the same type. Here, we propose a new method for generating a hybrid optical trap array (HOTA), where optical traps such as GPs, OVs, PVs, and Airy beams in the focal plane are combined arbitrarily. Also, the axial position and peak intensity of each them can be adjusted independently. The energy efficiency of this method is theoretically studied, while different micro-manipulations on multiple particles have been realized with the support of HOTA experimentally. The proposed method expands holographic optical tweezers’ capabilities and provides a new possibility of multi-functional optical micro-manipulation.

scholarly journals Positioning Accuracy in Holographic Optical Traps

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 559
Author(s):  
Frederic Català-Castro ◽  
Estela Martín-Badosa
Keyword(s):  
Optical Tweezers ◽  
Dynamic Control ◽  
Optical Trap ◽  
Optical Traps ◽  
Spatial Light Modulators ◽  
Positioning Accuracy ◽  
Light Modulators ◽  
Holographic Optical Tweezers ◽  
The One ◽  
Optically Trapped

Spatial light modulators (SLMs) have been widely used to achieve dynamic control of optical traps. Often, holographic optical tweezers have been presumed to provide nanometer or sub-nanometer positioning accuracy. It is known that some features concerning the digitalized structure of SLMs cause a loss in steering efficiency of the optical trap, but their effect on trap positioning accuracy has been scarcely analyzed. On the one hand, the SLM look-up-table, which we found to depend on laser power, produces positioning deviations when the trap is moved at the micron scale. On the other hand, phase quantization, which makes linear phase gratings become phase staircase profiles, leads to unexpected local errors in the steering angle. We have tracked optically trapped microspheres with sub-nanometer accuracy to study the effects on trap positioning, which can be as high as 2 nm in certain cases. We have also implemented a correction strategy that enabled the reduction of errors down to 0.3 nm.

High-Speed, Long-Distance Electric Traction

1905 ◽  
Vol 59 (1537supp) ◽  
pp. 24627-24628
Author(s):  
Charles A. Mudge
Keyword(s):  
High Speed ◽  
Long Distance ◽  
Electric Traction

scholarly journals Enhanced Signal-to-Noise and Fast Calibration of Optical Tweezers Using Single Trapping Events

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 570
Author(s):  
Alexander B. Stilgoe ◽  
Declan J. Armstrong ◽  
Halina Rubinsztein-Dunlop
Keyword(s):  
Brownian Motion ◽  
Optical Tweezers ◽  
Optical Trap ◽  
Force Transducer ◽  
Signal To Noise ◽  
Likelihood Estimator ◽  
Micro Fluidics ◽  
Large Numbers ◽  
Force Reconstruction ◽  
Micron Particle

The trap stiffness us the key property in using optical tweezers as a force transducer. Force reconstruction via maximum-likelihood-estimator analysis (FORMA) determines the optical trap stiffness based on estimation of the particle velocity from statistical trajectories. Using a modification of this technique, we determine the trap stiffness for a two micron particle within 2 ms to a precision of ∼10% using camera measurements at 10 kfps with the contribution of pixel noise to the signal being larger the level Brownian motion. This is done by observing a particle fall into an optical trap once at a high stiffness. This type of calibration is attractive, as it avoids the use of a nanopositioning stage, which makes it ideal for systems of large numbers of particles, e.g., micro-fluidics or active matter systems.

Thermal comfort analysis of a high-speed train cabin considering the solar radiation effects

2019 ◽  
Vol 29 (8) ◽  
pp. 1101-1117
Author(s):  
Lin Yang ◽  
Xiangdong Li ◽  
Jiyuan Tu
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
High Speed ◽  
Radiation Effects ◽  
Numerical Study ◽  
Thermal Conditions ◽  
Long Distance ◽  
High Speed Rail ◽  
Hot Weather ◽  
Cabin Environment

Due to the fast development of high-speed rail (HSR) around the world, high-speed trains (HSTs) are becoming a strong competitor against airliners in terms of long-distance travel. Compared with airliner cabins, HST cabins have much larger window sizes. When the big windows provide better lighting and view of the scenery, they also have significant effects on the thermal conditions in the cabins due to the solar radiation through them. This study presents a numerical study on the solar radiation on the thermal comfort in a typical HST cabin. The effect of solar radiation was discussed in terms of airflow pattern, temperature distribution and thermal comfort indices. Parametric studies with seven different daytime hours were carried out. The effect of using the roller curtain was also studied. The overall cabin air temperature, especially near passengers, was found to have significantly increased by solar radiation. Passengers sitting next to windows were recorded to have an obvious thermal comfort variation at different hours of the day. To improve the passengers’ comfort and reduce energy consumption during hot weather, the use of a curtain could effectively reduce the solar radiation effect in the cabin environment.

ORIENTATING MANIPULATION OF CYLINDRICAL PARTICLES WITH OPTICAL TWEEZERS

2008 ◽  
Vol 17 (04) ◽  
pp. 387-394 ◽  
Author(s):  
XIUDONG SUN ◽  
XUECONG LI ◽  
JIANLONG ZHANG
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Laser Beam ◽  
Optical Tweezers ◽  
Optical Trap ◽  
Polarization Direction ◽  
Beam Shape ◽  
E Coli ◽  
Potential Applications ◽  
Cylindrical Particles

Orientating manipulations of cylindrical particles were performed by optical tweezers. Vertical and horizontal manipulations of Escherichia coli (E. coli) were carried out by changing the trapping depth and the focused laser beam shape. It was found that carbon nanotubes bundles (CNTBs) could be rotated in the linear polarized optical trap until it orientated its long axis along the linear polarization direction of the laser beam. However, E.coli could not be orientated in this way. Corresponding mechanisms were discussed based on the anisomeric electric characters of CNTBs. These orientation technologies of cylindrical objects with optical trap have potential applications in assembling nano-electric devices.

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