An alternative technique, developed in the late 1990s by the Whitesides Research Group at Harvard University, allowed micron-scale features to be replicated by casting polydimethylsiloxane-silicon rubber (PDMS), creating an open channel that then had to be closed by a lid. Although these are extremely accurate and deliver the highest quality possible, they are also very expensive and slow. Traditionally, prototype microfluidic devices are produced using clean room-based microfabrication techniques such as lithography.
There is a clear need to complement existing techniques for the production of microfluidic devices with more rapid, cost-effective 3D printing technology that can create fluidically-sealed devices able to withstand the high pressures used in many applications. Microfluidics is a fast-growing field showing great potential for a wide range of applications, including point-of-care diagnostics, analytics, drug development, organ-on-a-chip, education, chemical synthesis and biomedical assays, as well as research and development. Until now, this has prevented the adoption of 3D printing technology for microfluidic applications. In addition, conventional 3D printing materials are unsuitable for microfluidic applications, as they are not chemically or biologically compatible, or transparent. Fabrication techniques such as clean room-based microfabrication, injection molding and milling and bonding are generally slow and expensive, and traditional 3D printers are unable to generate fluidically-sealed devices able to cope with the high pressures required. Prototyping of microfluidic devices presents a number of challenges. A selection of microfluidic chips created by the Fluidic Factory 3D printer.