The manufacturing of packaged capillary action microfluidic systems by means of CO₂ laser processing

In this article we demonstrate a simple yet robust rapid prototyping manufacturing technique for the construction of autonomous microfluidic capillary systems by means of CO2 laser processing. The final packaging of the microfluidic device is demonstrated using thermal lamination bonding and allows for a turnaround time of approximately 30 min to 3 h from activation of the laser system to device use. The low-cost CO2 laser system is capable of producing repeatable microfluidic structures with minimum feature sizes superior than 100-150 mu m over channel depths of more than 100 mu m. This system is utilised to create capillary pump and valve designs within poly (methyl methacrylate) (PMMA) substrates. Such components are part of advanced systems that can self initiate and maintain the flow of various volumes of fluids from an input to a collection reservoir, whilst also controlling the progression of the flow through the various demonstrated valve type structures. The resulting systems could prove a very useful alternative to traditional, non-integrated, fluidic actuation and flow control systems found on-chip, which generally require some form of energy input, have limited portable capabilities and require more complex fabrication procedures.