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Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
Because pulsed lasers store up energy and emit it in one extremely short pulse, rather than in a continuous beam, this results in extraordinarily high power levels during the brief pulse time. A typical pulse duration, indicated as tw in Figure 3.19b, is several nanoseconds (10−9 s), and a typical pulse carries enough energy (on the order of several J) to vaporize a small volume of tissue. The repetition rate is typically several pulses per second (1–10 Hz). This gives huge instantaneous powers during a pulse of over one million watts (1 megawatt), with correspondingly high power densities. One of the techniques for generating high-intensity optical pulses of very short duration is called chirped pulse amplification (CPA). Donna Strickland and Gérard Mourou, the scientists who invented this technology, were awarded the 2018 Nobel Prize in Physics. (They shared the Nobel Prize with Arthur Ashkin, who developed optical tweezers, devices in which laser light is used to trap microscopic objects, a valuable tool used to study and manipulate biological molecules and components of cells.)
Diagnosis: Nanosensors in Diagnosis and Medical Monitoring
Published in Harry F. Tibbals, Medical Nanotechnology and Nanomedicine, 2017
Tightly focused laser beams can form optical traps on the micro- to nanoscale, which can be used to manipulate cells and microparticles, as optical tweezers [230,231]. Polarized laser beams can be used to form optical vortex traps, where the central region of the trap has a lower optical intensity than the surrounding ring; this type of trap is superior for the manipulation of cells and other materials that are vulnerable to photochemical reactions or photothermal effects [232-235]. Optical vortex traps are a useful way of manipulating droplet samples in microfluidics [236,237].
Introduction
Published in Malgorzata Lekka, Cellular Analysis by Atomic Force Microscopy, 2017
The capability of cells to deform has been studied long time ago. One of the earliest reports of increased deformability of cancerous cells has been reported by Ochalek et al. [11]. In these studies, the microfiltration experiments were used to study the migration capability of B16 mouse melanoma cells. In the filtration experiment, the assumption was that all melanoma cells capable to metastase passed through the filter. This was justified by the condition that metastatic cells must be squeezed to go through the surrounding tissue matrix when they make their way into the circulatory systems where they are directed to establish distant settlements. However, the conclusion has been built by counting cells and quantifying the filtration time, not by the determination of cells mechanical properties. The pioneering study [12] showed the importance of mechanical properties to characterize cancerous cells. In these studies, the deformability of human bladder cancerous cells (cell lines: T24, Hu456, BC3726) was one order of magnitude larger than for their reference counterpartners (cell lines: Hu609, HCV29). These early results have been supported (and indirectly verified) by optical tweezers measurements. Using this latter, high throughput technique, three cell lines were compared, namely, a non-tumorigenic breast epithelial MCF10 cells, a non-motile, non-metastatic breast epithelial cancer MCF7 cells, and MCF7 cells transformed with phorbol ester causing the increase in the cancer cell invasiveness. The results showed significant increase of MCF7 cells deformability compared to MCF10 and non-transformed MCF7 ones [10].
Numerical investigation of blood flow and red blood cell rheology: the magnetic field effect
Published in Electromagnetic Biology and Medicine, 2022
Nazli Javadi Eshkalak, Habib Aminfar, Mousa Mohammadpourfard, Muhammed Hadi Taheri, Kaveh Ahookhosh
In addition to the numerical methods, some experimental studies have also been conducted to investigate red blood cells. Tsukada et al. (Tsukada Kosuke 2001) in an in vitro experiment measured the deformability of erythrocytes by using transparent microchannels on a crystal substrate. It was shown that the deformability of diabetic erythrocytes was considerably lower than that of normal erythrocytes, indicating that due to the impaired deformability in diabetic RBCs, the viscosity could change and the shear stress on the microvessel wall increase. Dao et al. (Dao 2003) investigated the mechanical deformation characteristics of erythrocytes by optical tweezers. They conducteda parametric study to develop quantitative models for the mechanics of deformation employing optical tweezers and the results demonstrated that there are connections between the RBC deformability and the progression of the disease. As a specimen, for the parasite-infected RBCs in malaria, it was evident that there are correlations between the membrane deformability decrease and the exposure to the parasite.
Biological membranes in EV biogenesis, stability, uptake, and cargo transfer: an ISEV position paper arising from the ISEV membranes and EVs workshop
Published in Journal of Extracellular Vesicles, 2019
Ashley E. Russell, Alexandra Sneider, Kenneth W. Witwer, Paolo Bergese, Suvendra N. Bhattacharyya, Alexander Cocks, Emanuele Cocucci, Uta Erdbrügger, Juan M. Falcon-Perez, David W. Freeman, Thomas M. Gallagher, Shuaishuai Hu, Yiyao Huang, Steven M. Jay, Shin-ichi Kano, Gregory Lavieu, Aleksandra Leszczynska, Alicia M. Llorente, Quan Lu, Vasiliki Mahairaki, Dillon C. Muth, Nicole Noren Hooten, Matias Ostrowski, Ilaria Prada, Susmita Sahoo, Tine Hiorth Schøyen, Lifu Sheng, Deanna Tesch, Guillaume Van Niel, Roosmarijn E. Vandenbroucke, Frederik J. Verweij, Ana V. Villar, Marca Wauben, Ann M. Wehman, Hang Yin, David Raul Francisco Carter, Pieter Vader
Alternative approaches to single-EV analysis are also being developed, including 3D-SEM, CLEM, AFM and Raman spectroscopy. However, these methods are less commonly available and do not offer high throughput analysis. AFM has been used to quantify the physical characteristics of EVs, such as stiffness, as well as for the visualization of EV budding. “Label free” methods are attractive, as labelling by itself can alter the EVs. The use of optical tweezers for studying and manipulating single, large EVs is also gaining traction [158]. Capillary electrophoresis techniques may also be implemented to allow for separation of EVs of different sizes or composition. Cryo-EM is another good tool for visualizing EVs since EM with immunogold labelling is the only technique that combines morphological information at high resolution and the specificity of labelling. A recommendation arising from this Workshop is for the field to improve and develop single-vesicle analysis techniques that will allow researchers to ask new, important questions related to all aspects of EV biology.
Numerical simulation of deformed red blood cell by utilizing neural network approach and finite element analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Ying Wang, Jianbing Sang, Rihan Ao, Yu Ma, Bowei Fu
Optical tweezers stretching involves the beads attached to the cell membrane and then be trapped with a laser. When the photons in the laser beam pass through the beads with high refractive index, the change of momentum will produce tension, and the applied force will push the beads to the focus of the laser beam. The technique can be used to stretch the cell along its axial direction and make them contract laterally. The schematic diagram of the experimental device is shown in Figure 1. Daxial and Dtrans are the axial and transverse diameters, respectively, and F is the applied external force.