title: A lithography-free procedure for fabricating three-dimensional microchannels using hydrogel molds.
abstract: We present a lithography-free procedure for fabricating intrinsically three-dimensional smooth-walled microchannels within poly(dimethylsiloxane) (PDMS) elastomer using hydrogel molds. In the fabrication process, small pieces of agarose gel ("wires" or "chips") are embedded in uncured PDMS composite, arranged in the shape of the desired microchannels, and used as molds to form the microchannels. The point of the process is that molds for creating junctions of microchannels such as T-junctions or cross-junctions can be robustly formed by simply grafting gel wires in uncured PDMS composite without using adhesive agents. The technical advantage of this method is that three-dimensional microstructures such as microchannels with circular cross sections, three-dimensionally arranged junctions or interchanges of microchannels can be flexibly designed and fabricated with a straightforward procedure without the need for any specialized equipment or layer-by-layer assemblage processes. This method provides a low-cost, green procedure for fabricating microfluidic devices and promises to make microfluidic processes more accessible and easy to implement in a variety of scientific fields.
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Japan.
authors.forename: Hirotada
authors.initials: H
authors.lastname: Hirama
authors.forename: Takahiro
authors.initials: T
authors.lastname: Odera
authors.forename: Toru
authors.initials: T
authors.lastname: Torii
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Moriguchi
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D020724:Elastomers / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000191:economics / Q000379:methods*; D012685:Sepharose / Q000737:chemistry
chemical_list: D004129:Dimethylpolysiloxanes; D020724:Elastomers; D020100:Hydrogels; C013830:baysilon; D012685:Sepharose