A team from Montana State University’s Department of Mechanical and Industrial Engineering has developed a new technique for 3D printing microfluidic devices. The new method is capable of 3D printing directly onto a glass substrate to create thin fluid channels measuring less than a millimeter in width. The novel process is reportedly faster and cheaper than more conventional microfluidic production methods.
The innovative research was led by Stephan Warnat, an assistant professor in MSU’s Norm Asbornson College of Engineering, and could have important applications in producing cost-effective custom prototypes of microfluidic chips. According to Warnat, the cost of the materials to make the chips is only about a dollar, while the turnaround time is only about a day, from start of production to final testing.
Traditionally, microfluidic chips are made using either an etching process or a process in which parts of the chip are masked and thin strips of material are chemically deposited. Glass has remained the most beneficial material for microfluidic chips because of its transparency, making it possibly to visualize the liquid clearly under the microscope. One of the challenges of 3D printing microfluidic channels has been the difficulty of printing onto glass without the channels becoming unbonded.
The process developed by the team addresses this problem and solves it. In its research, the team used a MiiCraft 50 DLP 3D printer and Clear BV007, a resin with low viscosity and transparency. By making adaptations to the printing process, the team was able to print the resin directly onto the glass. As a bonus, the material also bonded well with small sensors made from thin sheets of metal. These sensors, produced at the Montana Microfabrication Facility, can be integrated into microfluidic chips to measure electrical current and detect certain minerals in water.
“These 3D printers are pretty much available to anyone,” said Michael Neubauer, an MSU graduate student who co-authored the study. “Really what we’ve done is bring these techniques together in way that’s straightforward and that most people can accomplish in their labs. The hope is that other experts in their fields can follow these methods to come up with applications that are really cool and interesting.”
The 3D printing process will be implemented at Montana State University in Warnat’s lab, enabling the production of affordable micro-sensors for measuring water quality in streams and soil. The technology may also be used by MSU’s Center for Biofilm Engineering, which is interested in using the microfluidic devices to study microbes. “The low cost and small size of these sensors make them very attractive for use in environmental and industrial applications where you want to take lots of measurements in multiple locations,” explained Christine Foreman, professor in the Department of Chemical and Biological Engineering.
The research study was recently published in the journal Engineering Research Express.