Garcia-Webb M G, Taberner A J, Hogan N C, Hunter I W
Department of Bioengineering, Massachusetts Institute of Technology, 3-147 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Am J Physiol Heart Circ Physiol. 2007 Jul;293(1):H866-74. doi: 10.1152/ajpheart.01055.2006. Epub 2007 Feb 16.
The cardiac ventricular myocyte is a key experimental system for exploring the mechanical properties of the diseased and healthy heart. Millions of primary myocytes, which remain viable for 4-6 h, can be readily isolated from animal models. However, currently available instrumentation allows the mechanical properties of only a few physically loaded myocytes to be explored within 4-6 h. Here we describe a modular and inexpensive prototype instrument that could form the basis of an array of devices for probing the mechanical properties of single mammalian myocytes in parallel. This device would greatly increase the throughput of scientific experimentation and could be applied as a high-content screening instrument in the pharmaceutical industry. The instrument module consists of two independently controlled Lorentz force actuators-force transducers in the form of 0.025 x 1 x 5 mm stainless steel cantilevers with 0.5 m/N compliance and 360-Hz resonant frequency. Optical position sensors focused on each cantilever provide position and force resolution of <1 nm/ radicalHz and <2 nN/ radicalHz, respectively. The motor structure can produce peak displacements and forces of +/-200 mum and +/-400 microN, respectively. Custom Visual Basic.Net software provides data acquisition, signal processing, and digital control of cantilever position. The functionality of the instrument was demonstrated by implementation of novel methodologies for loading and attaching healthy mammalian ventricular myocytes to the force sensor and actuator and use of stochastic system identification techniques to measure their passive dynamic stiffness at various sarcomere lengths.
心室肌细胞是探索患病和健康心脏力学特性的关键实验系统。数百万个原代肌细胞可从动物模型中轻松分离出来，这些细胞能存活4至6小时。然而，目前可用的仪器仅能在4至6小时内探究少数几个承受物理负荷的肌细胞的力学特性。在此，我们描述了一种模块化且价格低廉的原型仪器，它可作为一系列用于并行探测单个哺乳动物肌细胞力学特性的设备的基础。该设备将极大提高科学实验的通量，并可作为制药行业的高内涵筛选仪器。仪器模块由两个独立控制的洛伦兹力致动器组成，它们是力传感器，采用0.025×1×5毫米的不锈钢悬臂形式，柔度为0.5米/牛顿，共振频率为360赫兹。聚焦在每个悬臂上的光学位置传感器分别提供小于1纳米/根号赫兹的位置分辨率和小于2纳牛顿/根号赫兹的力分辨率。电机结构可分别产生±200微米的峰值位移和±400微牛顿的峰值力。定制的Visual Basic.Net软件提供数据采集、信号处理以及悬臂位置的数字控制。通过实施将健康哺乳动物心室肌细胞加载并附着到力传感器和致动器上的新方法，以及使用随机系统识别技术在不同肌节长度下测量其被动动态刚度，证明了该仪器的功能。
