Researchers from the University of Freiburg, ETH Zurich, the University of Würzburg and micro-scale 3D printing company Nanoscribe GmbH are pioneering a method for producing hollow 3D glass structures for microfluidic applications. The innovative technique is based on Nanoscribe’s microfabrication technology and has proven capable of producing intricate microfluidic structures made of fused silica glass.
Using glass for microfluidic and lab-on-a-chip devices could be highly beneficial, as quartz glass demonstrates excellent optical, chemical and mechanical properties as well as long-term stability. Up until now, however, one of the main challenges in using glass for such applications has been producing microstructures from it.
The unique process developed by the researchers and Nanoscribe overcomes this challenge by using sacrificial template replication to produce 3D microfluidic channels using transparent silica glass. In the research, essential 3D microstructures were produced using Nanoscribe’s micro-scale 3D printer.
In short, the process consists of first 3D printing a polymer microstructure. This microstructure is then cast in a liquid nanocomposite glass material, which is subsequently solidified on top of the polymer template with UV light. A thermal treatment is then applied to the structure, transforming the nanocomposite material into fused silica glass and melting the sacrificial polymer structure from within. The result after the treatment process—which reaches temperatures up to 1,300 degrees Celsius—is a strong, hollow glass structure with complex micro-channels.
At this stage in the research project, the joint team has successfully produced channels as small as 7 micrometers in diameter. Additionally, the precise out-of-plane channel guidance achieved in the test parts—including the mixer pictured above—demonstrates the process’ viability for producing complex glass structures.
Going forward, the joint research team hopes to further develop the technique to the point where it is ready for the industrial market. From Nanoscribe’s perspective, the research is also laying the groundwork for the use of glass materials with its microfabrication technology.
The research study was recently published in the journal Nature Communications.