Rapid design and prototyping of microfluidic chips via computer numerical control micromilling and anisotropic shrinking of stressed polystyrene sheets

The use of microfluidics has benefitted numerous scientific disciplines towards further advancements in sectors such as plant and pollution monitoring, diagnostic systems, detection of pathogenic microorganisms, and detection of harmful substances. Advancements in scientific disciplines are achieved when researchers have access to required materials and equipment. This is true of microfluidic technologies. However, an on-going challenge to widespread access to microfluidic technologies is the expense and complexity of microfluidic fabrication systems. In the last decade, numerous efforts have been realized for the development of microfluidic fabrication methods that do not require a cleanroom facility and other expensive equipment. These fabrication methods typically have varying parameters and restrictions that inhibit the speed of fabrication and customization of microfluidic chip features. The following work explores a straightforward method for rapid fabrication of microfluidic chip systems using a combination of stressed polystyrene sheets and computerized micromilling. A quantitative analysis of the anisotropic shrinking properties of the stressed polystyrene sheet is completed with experimentation on various geometric features. These experiments will aid in future use of this technology. The proposed fabrication method can inexpensively fabricate a flow-based microfluidic gradient mixer in under an hour with inexpensive fabrication equipment.