title: Fabrication of circular microfluidic channels by combining mechanical micromilling and soft lithography.
abstract: The fabrication of microfluidic channels with complex three-dimensional (3D) geometries presents a major challenge to the field of microfluidics, because conventional lithography methods are mainly limited to rectangular cross-sections. In this paper, we demonstrate the use of mechanical micromachining to fabricate microfluidic channels with complex cross-sectional geometries. Micro-scale milling tools are first used to fabricate semi-circular patterns on planar metallic surfaces to create a master mold. The micromilled pattern is then transferred to polydimethylsiloxane (PDMS) through a two-step reverse molding process. Using these semi-circular PDMS channels, circular cross-sectioned microchannels are created by aligning and adhering two channels face-to-face. Straight and serpentine-shaped microchannels were fabricated, and the channel geometry and precision of the metallic master and PDMS molds were assessed through scanning electron microscopy and non-contact profilometry. Channel functionality was tested by perfusion of liquid through the channels. This work demonstrates that micromachining enabled soft lithography is capable of fabricating non-rectangular cross-section channels for microfluidic applications. We believe that this approach will be important for many fields from biomimetics and vascular engineering to microfabrication and microreactor technologies.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburg, PA 15213, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Wilson
authors.forename: Nithyanand
authors.initials: N
authors.lastname: Kota
authors.forename: YongTae
authors.initials: Y
authors.lastname: Kim
authors.forename: Yadong
authors.initials: Y
authors.lastname: Wang
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
authors.forename: Philip R
authors.initials: PR
authors.lastname: LeDuc
authors.forename: O Burak
authors.initials: OB
authors.lastname: Ozdoganlar
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D055595:Mechanical Phenomena; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D055616:Microtechnology / Q000379:methods*; D011327:Printing / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; C013830:baysilon