其他品牌 品牌
代理商厂商性质
北京市所在地
细胞组织力学特性定量测试分析系统
在活细胞或3D组织内部执行同时进行力测量和主动/被动微流变测试的256个光学陷阱实验。同时捕获256个目标分子或者粒子，浸没式细胞或组织力学特性定量测量，无需校准。
基本功能概述
陷阱的产生和处理
免校准力测量
振荡程序
功率谱采集
主动和被动微流变学
粒子操纵和力测量
光阱的产生
粒子操纵
免校准力测量
应用概述：
细胞操作
细胞粘附力
细胞间相互作用
绳索牵引
细胞拉伸
主动和被动微流变学
Papers:
Optical trapping has become an optimal choice for biological research at the microscale due to its noninvasiveperformance and accessibility for quantitative studies, especially on the forces involved inbiological processes. However, reliable force measurements depend on the calibration of the opticaltraps, which is different for each experiment and hence requires high control of the local variables,especially of the trapped object geometry. Many biological samples have an elongated, rod-likeshape, such as chromosomes, intracellular organelles (e.g., peroxisomes), membrane tubules, certainmicroalgae, and a wide variety of bacteria and parasites. This type of samples often requires severaloptical traps to stabilize and orient them in the correct spatial direction, making it more difficult todetermine the total force applied. Here, we manipulate glass microcylinders with holographic opticaltweezers and show the accurate measurement of drag forces by calibration-free direct detection ofbeam momentum.
Measuring forces inside living cells is still a challenge due the characteristics of the trapped organelles (non-spherical, unknown size and index of refraction) and the cell cytoplasm surrounding them heterogeneous and dynamic, non-purely viscous). Here, we show how two very recent methods overcome these limitations: on the one hand, forces can be measured in such environment by the direct detection of changes in the light momentum; on the other hand, an active-passive calibration technique provides both the stiffness of the optical trap as well as the local viscoelastic properties of the cell cytoplasm.
In molecular studies, an optically trapped bead may be functionalized to attach to a specific molecule, whereas in cell studies, direct manipulation with the optical field is usually employed. Using this approach, several methods may be used to measure forces with an optical trap. However, each has its limitations and requires an accurate knowledge of the sample parameters.6,7 In particular, force measurements can be challenging when working with nonspherical particles or in environments with an inhomogeneous viscosity, such as inside the cell. Recent developments in the field are moving toward obtaining direct force measurements by detecting light momentum changes. For this approach, the calibration factor only comes from the detection instrumentation and negates the requirement to recalibrate for changes in experimental conditions”.
“Using optical tweezers, we directly measured a holding force of 64 ± 16 fN, which was necessary to counteract the effective self-propulsion force generated by a single nanomotor. The successful demonstration of biocompatible enzyme-powered active nanomotors using biologically benign fuels has a great potential for future biomedical applications.”
Here, the authors present a comparison between two different methods for measuring forces inside living cells and provide measurements of the stall force of kinesin in vivo using the momentum-based approach. More information at:bioweb.bio.uci.edu/sgross/publications.html
This manuscript shows the relation between the determination of momentum measurements and back-focal-plane interferometry, and details how to obtain the force response of the sensor both from first principles and from its connection with trap stiffness calibration.
In this work, the authors show the feasibility of combining optical tweezers (single-beam gradient traps) with the determination of forces using the measurement of the light momentum change.
