An integrated optical stretcher and microfluidic system for biological physics

光的光子在撞击物质时携带动量和作用力。在宏观世界中，这些力量相对较小，没有人注意到。在微观世界中，光动量可以产生重大的机械后果。利用这一点，光学陷阱已经被开发出来，其中聚焦的光可以用来捕获流体介质中的介电粒子。最近的一项发展将光的使用从简单地捕捉物体扩展到能够机械地拉伸它。所谓的“光学担架”已经成为一种重要且易于实施的工具，它可以捕获单个活细胞，同时能够机械地拉伸它们。与需要大量光学和电子元件的传统光学陷阱不同，光学展宽器只需两束未聚焦的光束以相反的方式对准即可。当细胞与这两根梁相交时，力的平衡将作用于细胞，因为作用在细胞上的净力将为零。然而，作用在与光源的点相反的细胞膜上的力将大于零，从而导致机械拉伸。结合光学显微镜，人们现在能够对细胞进行机械测量，根据这些测量检测各种疾病状态，并以高通量的方式成像机械变形。在这项提案中，我们正在寻求资金，以建立一个集成的光学担架和微流控系统，不仅可以捕获和机械拉伸细胞，而且可以通过微流控交换、高通量机械分析、生物物理传感和下游细胞分选来同时改变细胞的生理环境。这样的系统在商业上是不可用的，而且将是加拿大和国际上第一个此类系统。这将为HQP在生物物理跨学科科学方面的培训提供独特的机会，获得仪器、显微镜、光学和细胞/分子生物学方面的经验。所要求的系统还将能够调查细胞的医学相关生物物理性质，其应用范围从加强我们对细胞生物学的了解到开发高通量传感和筛选技术。

Photons of light carry momentum and exert forces when they impinge matter. In the macroscopic world, these forces are relatively small and go unnoticed. In the microscopic world, light momentum can have significant mechanical consequences. Taking advantage of this, optical traps have been developed in which focussed light can be used to trap dielectric particles in a fluid medium. A recent development has extended the use of light from simply trapping an object, to being able to mechanically stretch it. The so called "Optical Stretcher" has become an important and easily implemented tool in which to trap single living cells while being able to mechanically stretch them. Unlike a traditional optical trap which requires extensive optical and electronic components, the optical stretcher relies simply on two unfocussed beams of light being aligned in an opposed manner. When a cell intersects with these two beams the balance of forces will act to trap the cell because the net force acting on it will be zero. However, the forces acting on the cell membrane opposite from the point of the light source will be greater than zero which results in a mechanical stretch. In combination with optical microscopy one is now able to perform mechanical measurements of cells, detect various disease states based on these measurements and image mechanical deformation in a high-throughput manner. In this proposal we are seeking funds to build an integrated optical stretcher and microfluidic system not only to trap and mechanically stretch cells, but also to simultaneously change their physiological environment via microfluidic exchange, high throughput mechanical analysis, biophysical sensing, and downstream cell sorting. Such a system is not commercially available and will be the first of its kind in Canada and internationally. This will provide a unique opportunity for HQP training in the interdisciplinary science of biological physics, gaining experience in instrumentation, microscopy, optics and cell/molecular biology. The requested system will also enable the investigation of medically relevant biophysical properties of cells with applications ranging from enhancing our understanding of cell biology to developing high-throughput sensing and screening technologies.