Manipulation Of Optical Tweezers Research Articles

Quantitative Investigation of the Link between Actin Cytoskeleton Dynamics and Cellular Behavior.

Actin cytoskeleton reorganization, which is governed by actin-associated proteins, has a close relationship with the change of cell biological behavior. However, a perceived understanding of how actin mechanical property links to cell biological property remains unclear. This paper reports a label-free biomarker to indicate this interrelationship by using the actin cytoskeleton model and optical tweezers (OT) manipulation technology. Both biophysical and biochemical methods were employed, respectively, as stimuli for two case studies. By comparing the mechanical and biological experiment results of the leukemia cells under electrical field exposure and human mesenchymal stem cells (hMSC) under adipogenesis differentiation, we concluded that β-actin can function as an indicator in characterizing the alteration of cellular biological behavior during the change of actin cytoskeleton mechanical property. This study demonstrated an effective way to probe a quantitative understanding of how actin cytoskeleton reorganization reflects the interrelation between cell mechanical property and cell biological behavior.

Design of Optical Tweezers Manipulation Control System Based on Novel Self-Organizing Fuzzy Cerebellar Model Neural Network

Holographic optical tweezers have unique non-physical contact and can manipulate and control single or multiple cells in a non-invasive way. In this paper, the dynamics model of the cells captured by the optical trap is analyzed, and a control system based on a novel self-organizing fuzzy cerebellar model neural network (NSOFCMNN) is proposed and applied to the cell manipulation control of holographic optical tweezers. This control system consists of a main controller using the NSOFCMNN with a new self-organization mechanism, a robust compensation controller, and a higher order sliding mode. It can accurately move the captured cells to the expected position through the optical trap generated by the holographic optical tweezers system. Both the layers and blocks of the proposed NSOFCMNN can be adjusted online according to the new self-organization mechanism. The compensation controller is used to eliminate the approximation errors. The higher order sliding surface can enhance the performance of controllers. The distances between cells are considered in order to further realize multi-cell cooperative control. In addition, the stability and convergence of the proposed NSOFCMNN are proved by the Lyapunov function, and the learning law is updated online by the gradient descent method. The simulation results show that the control system based on the proposed NSOFCMNN can effectively complete the cell manipulation task of optical tweezers and has better control performance than other neural network controllers.

Automated Optical Tweezers Manipulation to Transfer Mitochondria from Fetal to Adult MSCs to Improve Antiaging Gene Expressions (Small 38/2021)

Mitochondrial Transfer In article number 2103086, Gang Li, Dong Sun, and co-workers present a novel method of controlling the quality and quantity of mitochondria transferred to single cells using an automated optical tweezer-based micromanipulation system. The transfer of isolated mitochondria from fetal mesenchymal stem cells (fMSCs) to adult mesenchymal stem cells (aMSCs) by the developed system can significantly increase the anti-aging and metabolic gene expressions in the aMSCs.

Automated Optical Tweezers Manipulation to Transfer Mitochondria from Fetal to Adult MSCs to Improve Antiaging Gene Expressions.

Mitochondrial dysfunction is considered to be an important factor that leads to aging and premature aging diseases. Transferring mitochondria to cells is an emerging and promising technique for the therapy of mitochondrial deoxyribonucleic acid (mtDNA)-related diseases. This paper presents a unique method of controlling the quality and quantity of mitochondria transferred to single cells using an automated optical tweezer-based micromanipulation system. The proposed method can automatically, accurately, and efficiently collect and transport healthy mitochondria to cells, and the recipient cells then take up the mitochondria through endocytosis. The results of the study reveal the possibility of using mitochondria from fetal mesenchymal stem cells (fMSCs) as a potential source to reverse the aging-related phenotype and improve metabolic activities in adult mesenchymal stem cells (aMSCs). The results of the quantitative polymerase chain reaction analysis show that the transfer of isolated mitochondria from fMSCs to a single aMSC can significantly increase the antiaging and metabolic gene expression in the aMSC. The proposed mitochondrial transfer method can greatly promote precision medicine for cell therapy of mtDNA-related diseases.

Validity of cylindrical approximation for spherical birefringent microparticles in rotational optical tweezers

Rotational manipulation of microscopic birefringent particles has conventionally been done by manoeuvring the polarization of the trapping light in optical tweezers. The torque on the particle is a sum of contributions from the linear polarization and the circular polarization, while assuming that the difference in optical path lengths between the extraordinary and the ordinary components of polarization depends upon the wavelength of light, the thickness of the particle and the birefringence. Generally, the thickness of spherical microparticles is assumed to be the diameter which renders the particle appear cylindrical. We test this hypothesis for sizes relevant towards optical tweezers manipulation. We find that for a range of particles from the Rayleigh regime to the early Mie regime, the approximation holds good.

Three-Dimensional Pose Estimation of Optically Transparent Microrobots

The use of microrobots for cell manipulation has a range of applications in biomedical research. Direct sensing of microrobot three-dimensional (3D) position and orientation, however, is practically challenging due to the small scale involved. This letter proposes a vision-based method for estimating the 3D pose of optically transparent microrobots based on Optical Tweezers (OT) manipulation by using Convolutional Neural Networks (CNNs). A model-based approach is used to generate the large training set required for CNNs. Detailed validation is performed to demonstrate the experimental use of the technique.

Generation of an optical ball bearing facilitated by coupling between handedness of polarization of light and helicity of its phase

We report on mutual transformation of spin and orbital angular momenta (SAM and OAM) of light upon tight focusing of circularly polarized vortex beams. In some regions of the focal spot, the OAM of light changes by a value ±2ℏ, while the circular polarization (CP) there reverses its rotation direction, resulting in adjacent rings (or core and adjacent ring) of opposite CP handedness. Moreover, the SAM has a transverse angular momentum (AM) component. We show that while the whole pattern rotates around the optical axis at the rate of the optical frequency divided by the value of total AM, the 3D SAM “balls” between adjacent rings (or between a ring and a core) spin in an opposite direction at the rate of the optical frequency, constituting an optical analog of a ball bearing. The applications include manipulation of particles, e.g., optical tweezers or spanners.

Automated Transportation of Biological Cells for Multiple Processing Steps in Cell Surgery

Most studies on automated cell transportation are single-task oriented. Results from these investigations hardly meet the increasing demand for emerging cell surgery operations that usually require a series of manipulation tasks with multiple processing steps. In this paper, automated cell transportation to accomplish a multistep process in cell surgery was investigated. A novel control system that can manipulate grouped cells to move into different task regions sequentially and continuously without interruption was developed based on a robot-aided optical tweezers manipulation system. A potential field-based controller was designed to achieve multistep processing control, where the new concepts of contractive coalition and switching region were incorporated into tweezers–cell coalition. The success of this controller lies in simultaneously controlling the positions of the optical tweezers, trapping multiple cells effectively, and avoiding collisions in a unified manner. Simulations and experiments of transferring a group of cells to a number of task regions were performed to demonstrate the effectiveness of the proposed approach. Note to Practitioners —This paper was motivated by the challenging problem of automated transportation of grouped cells to several predefined task regions in emerging cell surgery with multiple processing steps. Existing automated cell transportation studies are mainly single-task oriented, thereby making them inapplicable to cell surgery operations, because a series of sequential processing steps are usually involved in these operations. This paper provides a novel control strategy based on a robot-aided optical tweezers manipulation system to efficiently transport cells into different task regions sequentially without interruption. Unlike the previous cell transportation studies where the goal positions of single cells must be specified early, here only the desired task regions are identified in the controller implementation, making the proposed strategy a better fit for actual cell surgery practice.

Automated Translational and Rotational Control of Biological Cells With a Robot-Aided Optical Tweezers Manipulation System

Research and biomedical applications in cell surgery require transportation and rotation of biological cells. In these cell manipulation tasks, the cell of interest must be translated and oriented properly such that the desired component, such as the polar body or other organelles, can be imaged with optical microscopy. This paper presents a holographic optical tweezers (HOT) based system to carry out automated translational control in the plane, and rotational control about one rotational axes of a suspended cell. Based on the proposed general equations of motion of the cell, held in an optical trap, two controllers, one for cell translational and one for rotational control, are developed to translate and orient the cells to the desired position and orientation in a sequential manner. Experiments are performed to demonstrate the effectiveness of the proposed approach.

Frequency‐dependent cell death by optical tweezers manipulation

Optical tweezers were used to scan individual Chronic Myelogenous Leukemia cells to determine if the cell death depends on the scanning conditions. Although increasing the scanning frequency or amplitude means greater force applied to the cells, their effects on cell death are not a simple increasing trend, as observed in the optical microscopy. Indeed, cell death sharply increased at particular screening frequencies and amplitudes, whereas other frequencies or amplitudes were less detrimental. These results suggest that cell damage was more sensitive to certain scanning conditions, rather than simply high-applied forces.

Scanning x-ray microdiffraction of optically manipulated liposomes

We show optical tweezers manipulation of individual micron-sized samples investigating at the same time their inner nanostructure by synchrotron diffraction experiments. The validity of this technique is demonstrated for clusters of multilamellar liposomes trapped in single and multiple positions in the optical path of a microfocused x-ray beam and analyzed in a microscanning mode. The signal to background ratio of the first order peak shows that single liposome measurements are feasible. Multiple trapping by means of diffractive optical elements is demonstrated as an effective manipulation tool for future x-ray diffraction studies of the interaction between different sample entities.

MOLECULE-UP FABRICATION AND MANIPULATION OF LIPID NANOTUBES

Self-assembling behavior of both a cardanol-appended glycolipid mixture and the fractionated four components has been examined in aqueous solutions. The cardanyl glucoside mixture differing in the degree of unsaturation in the hydrophobic chain was found to self-assemble in water to form open-ended nanotube structures with 10–15 nm inner diameters. The pure saturated homologue produced twisted helical ribbons through self-assembly, whereas the monoene derivative gave tubular structures. The rational control of helical and tubular morphologies has been achieved by a combinatorial approach through the binary self-assembly of the saturated and monoene derivatives. The flexural rigidity of a single lipid nanotube was first evaluated using optical tweezers manipulation and then compared with that of natural microtubules.