3D microfluidics in PDMS: manufacturing with 3D molding

This paper describes a procedure to rapidly design and fabricate 3D microfluidic systems in the elastomer polydimethysiloxane (PDMS) using 3D molding, without the use of photolithography. A microfluidic system of channels is designed in a CAD program with the final fluid path being fully three dimensional. The initial design is inverted to create a negative mold which is 3D printed; the resolution of the printer is the limiting design factor. PDMS is cast in the 3D-printed mold in multiple pieces which are then cured together to create the final 3D device. No plasma bonding is required for the PDMS-PDMS sealing, a "glue" of uncured PDMS is used instead. A sample device of interlocking ring voids is presented to demonstrate the fabrication of a complex geometry which would be nearly impossible to manufacture via traditional soft lithography methods utilizing photolithography.