Microfluidics enable the integration of multiple analytical processes in a hand-held device making on-site analysis possible. However, the fabrication is inherently challenging, especially when a 3D architecture is required. Current methods are mainly 2D based, expensive, or time consuming with misalignment and leaking being the most common problems. A cost-effective approach that allows flexible and rapid prototyping during the research phase and also compatible with commercial mass production is highly desirable.

Here, we explore the microfabrication capabilities of a consumer-focused 3D printer. 3D printers have been used previously to construct soft-lithography templates.¹  Recently, Kitson et al.²  used one that extrudes opaque plastic to fabricate microdevices for chemical synthesis. While this demonstrates the value of 3D printing for microfabrication, their approach was slow and it was impossible to visualise inside the microdevice. Alternatively, we used a printer with sequential patterning. Instead of point-by-point printing, 50 µm thick layers are exposed in two dimensions using a computer-projector coupled with a vertical stage. 3D microfluidic devices can be printed within few minutes using a clear photocurable resin – ideas can be translated into 3D design, printed, and tested within few hours at a very low cost. Raised features as small as 100 µm and through-features (microchannels, holes, etc) as small as 250 µm could be constructed by adjusting the curing time of the resin. These devices are compatible with fluorescence detection and can incorporate a range of microfluidic tools including mixing, gradient generation, droplet generation, and electrophoresis.