Design and fabrication of a micro fluidic circuit for the separation of micron sized particles

Abstract

The development of a micro fluidic circuit for the separation of micro particles is being investigated. There are a wide range of available separation techniques such as acoustic, laminar flow, split flow, optical trapping and centrifugal forces. The physical phenomena occurring at the micron level influences the design of the circuit as well as the behaviour of the particles within the circuit. Research is being directed towards the use of physical forces such as laminar flow and away from using external forces to drive flow and perform separation, this simplifies the circuit design. These phenomena can be manipulated in circuit design to suit specific applications. The present study focuses on the design considerations for circuits used in separation applications and the manufacturing of suitable standard particles, using dendrisphere technology. The particles used in this study are polyethyleneimine crosslinked with glutaraldehyde using an emulsion based technique. The versatility of these particles includes the ability to customise and functionalise them to suit a specific study. The modification of the technique for generating a variety of particle sizes is being investigated. The particles are stained to improve visualisation and assess qualitative discrimination of the different sized particles. The optical signature of the particles can be used advantageously in quantifying separation rather then particle counting. The particles will be used as standards to precisely evaluate the sorting ability of the micro fluidic circuits. This will give quantitative results of the circuit performance as well as establish the limitations of the system.