CO2 laser machining of fully packaged autonomous microfluidic systems

In this article we demonstrate a simple yet robust CO2-laser etching rapid prototyping technique for the construction of autonomous microfluidic capillary systems. The final packaging of the microfluidic device is demonstrated using both thermal and adhesive based lamination bonding and allows for a turnaround time of approximately 30 minutes to 3 hours 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 100–150µm over channel depths of more than 150µm. This system is utilised to create capillary pump and valve designs within poly(methyl methacrylate) (PMMA) substrates. Such components are utilised to create 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 simple and advanced valve type structures demonstrated. Such 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.