Showing papers on "Optical stretcher published in 2019"

The Role of the Optical Stretcher Is Crucial in the Investigation of Cell Mechanics Regulating Cell Adhesion and Motility.

Abstract: The mechanical properties of cells, tissues, and the surrounding extracellular matrix environment play important roles in the process of cell adhesion and migration. In physiological and pathological processes of the cells, such as wound healing and cancer, the capacity to migrate through the extracellular matrix is crucial. Hence biophysical techniques were used to determine the mechanical properties of cells that facilitate the various migratory capacities. Since the field of mechanobiology is rapidly growing, the reliable and reproducible characterization of cell mechanics is required that facilitates the adhesion and migration of cells. One of these cell mechanical techniques is the optical stretching device, which was originally developed to investigate the mechanical properties of cells, such as the deformation of single cells in suspension. After discussing the strengths and weaknesses of the technology, the latest findings in optical stretching-based cell mechanics are presented in this review. Finally, the mechanical properties of cells are correlated with their migratory potential and it is pointed out how the inhibition of biomolecules that contribute to the to the maintenance of cytoskeletal structures in cells affect their mechanical deformability.

3D Electro-Rotation of Single Cells

Abstract: Dielectrophoresis microfluidic chips have been widely used in various biological applications due to their advantages of convenient operation, high throughput, and low cost. However, most ...

Deformation of single cells - Optical two-beam traps and more

Abstract: An optical two-beam trap composed from two counter propagating laser beams is an interesting setup due to the ability of the system to trap, hold, and stretch soft biological objects like vesicles or single cells. Because of this functionality, the system was also named the optical stretcher by Jochen Guck, Josep Kaas and co-workers almost 20 years ago. In a favorable setup, the two opposing laser beams meet with equal intensities in the middle of a fluidic channel in which cells may ow past, be trapped, stretched, and allowed to move on, giving the promise of a high throughput device. Yet, single beam optical traps, aka optical tweezers, by far outnumber the existing optical stretchers in research labs throughout the world. The ability to easily construct an optical stretcher setup in a low-cost material would possibly imply more frequent use of the optical stretching technique. Here, we discuss advantages and disadvantages of choice of material and methodology for chip assembly and chip production. For high throughput investigations of stretching deformation of single cells, optical stretching is, however, out-performed by hydrodynamic deformability assays. As we will discuss, injection molded polymer chips may with advantage be applied both for optical stretching and for hydrodynamic deformability experiments.

Computational Model of Optical Stretcher

Abstract: Understanding the biophysical properties of cells is one of the highly researched areas in recent years. There are many examples of the usefulness of this knowledge, such as [1], where the deformability of cells is used as a marker for distinguishing malignant cells. Thus the motivation to model elastic cells with a nucleus is quite strong and we are currently working on a computational model of a cell with a nucleus. In order to obtain a working model, one must take several steps. Among them is the calibration process. For this step, we chose biological experiment where cells are stretched using optical traps. Using this method, the cell is stretched more linearly then in experiments with holders, such as silica beads, attached to the cell. That and the fact that this method was used on circulating tumour cells (CTC) are the reasons we chose this particular experiment. In this work, we focus on the simulation of the optical stretcher and its validation for our further work. We first explain the mechanical principles of the biological experiment. Then we discuss our approach to modelling the stretching force that is applied to the surface of the cell. Afterwards, we use this method on our calibrated RBC model and compare the results from the simulations with the analytical shape the cell should achieve with a given set of laser parameters. This is the first step in obtaining calibration simulation for a model of CTC.

Non-contact trapping and stretching of biological cells using dual-beam optical stretcher on microfluidic platform

Abstract: Optical stretcher is a tool in which two counter-propagating, slightly diverging, and identical laser beams are used to trap and axially stretch microparticles in the path of light In this work, we utilized the dual-beam optical stretcher setup to trap and stretch human embryonic kidney (HEK) cells and mammalian breast cancer (MBC) cells Experiments were performed by exposing the HEK cells to counter-propagating laser beams for 30 seconds at powers ranging from 100 mW to 561 mW It was observed that the percentage of cell deformation increased from 167% at 100 mW to 405% at 561 mW optical power The MBC cells exhibited significantly higher cell stretching compared to HEK cells at the same power (80 mW) Moreover, the minimum trapping power in HEK cells was 805mW as compared to 652mW in MBC cells This study provides useful insights into the characterization of cytoskeletal elasticity in different cell types based on non-contact optical cell stretching