Cutting edge microfluidics: Xurography and a microwave

Abstract

Microfluidic technologies enable precise fluidic manipulation at the microscale, with applications ranging from inexpensive medical diagnostics to automaton devices for extraterrestrial in situ analysis. However, development of microfluidic tools typically requires high-maintenance infrastructure and resource-intensive development processes, limiting their broad adoption. Furthermore, the development of effective microfluidic tools requires iterative design processes, multiplicatively increasing development time and cost. Rapid prototyping techniques minimize these expenses, accelerating development time and reducing manufacturing cost of microfluidic devices. Here, we use the print-and-peel (PAP) technique of xurography to fabricate master molds in conjunction with microwave thermal processing of polydimethylsiloxane (PDMS) to rapidly fabricate PDMS-based microfluidics. Three types of tape (3M Blue Platinum, PVC and Kapton Tape) and three types of backing substrates (Soda lime glass, Silicon, Ceramic glass) were employed, enabling fabrication of microfluidic devices from design to device in as little as five minutes. Minimum feature widths of ˜200 μm and feature heights of ˜60 μm were determined. Proof-of-concept devices made using these methods were employed for electrophoretic flow focusing applications. To the best of our knowledge, this process represents the most rapid method for fabrication of PDMS microfluidics to date due to microwave thermal processing, enabling curing of PDMS in as little as 90 s. This work can significantly minimize device fabrication time and the start-up cost of fabrication infrastructure, enhancing efficiency and making microfluidics accessible to a broader user base.