Passive fractionation of colloids and cells using optofluidics：胶体电池使用微流控光学被动分馏.ppt

* * * * Flow of microparticles or cells through a fluidic channel A coaxially aligned loosely focused laser beam is coupled to the channel in the direction opposite to the flow Particle experiences viscous drag force and radiation force acting against each other Reaches an equilibirium position depending on size, shape or refractive index – retention distance * * * * We designed microfluidic chip in which PCF can be inserted in a predefined fiber insertion channel Fiber channel is coaxially pre-aligned with the fluidic channel so that no further alignment is required to achieve chromatography Since PCF is holly, we devised a novel capping methodology so as to prevent any capillary action through the holes of PCF once the fiber is inserted to the channel The system is used for size driven and refractive index driven separation of colloids as you can see in this video. The fractionation was done with a 1070 fiber laser The retention distances of various sizes and refractive indices of colloids are experimentally obtained and compared with that of the ray optics model shown in the previous slide. The experimental result is comparable with that of the theory * * * * * * * * * * * * * Optical Manipulation Group, University of St Andrews SFM-11 Internet invited lecture Praveen C. Ashok and Kishan Dholakia Passive Fractionation of Colloids and Cells Using Optofluidics Optical Manipulation Group, University of St Andrews, Scotland Cell or colloidal fractionation - rationale Possible tools that can be used Optical fractionation Active vs. Passive sorting (Why passive fractionation?) Active sorting Passive sorting High throughput with fluorescence detection Relatively low throughput Requires external tagging for fluorescence based fractionation External tagging not necessary. Rely upon inherent properties of sample – size, shape or refractive index Techniques like Fluorescence Activated Cell Sorting (FACS) is an already established technique Proof of principle level demon