Monolithic Microfabricated Valves and Pumps by Multilayer Soft Lithography

Abstract

Soft lithography is an alternative to silicon-based micromachining that uses replica molding of nontraditional elastomeric materials to fabricate stamps and microfluidic channels. We describe here an extension to the soft lithography paradigm, multilayer soft lithography, with which devices consisting of multiple layers may be fabricated from soft materials. We used this technique to build active microfluidic systems containing on-off valves, switching valves, and pumps entirely out of elastomer. The softness of these materials allows the device areas to be reduced by more than two orders of magnitude compared with silicon-based devices. The other advantages of soft lithography, such as rapid prototyping, ease of fabrication, and biocompatibility, are retained.

In vitro blood flow in a rectangular PDMS microchannel: experimental observations using a confocal micro-PIV system

“…PDMS is an elastomeric and biocompatible material. The typical ultimate tensile stress (UTS) for PDMS ranges from 3.9 MPa to 10.8 MPa (Mata et al 2005), whereas the Young's elastic modulus (E) has a value of ∼0.75MPa (Unger et al 2000). The UTS and E of the blood vessels has values from 0.4 MPa to 1.4 MPa (Holzapfel et al 2005) and ∼2.5 MPa (Steiger et al 1989) respectively.…”

3-dimensional electrode patterning within a microfluidic channel using metal ion implantation

“…Such control has been demonstrated utilizing mechanical, electrical, thermal and optical force methods. [3][4][5][6][7][8][9][10] Electrical methods require the integration of electrodes to the microfluidic chip. If an electric field is applied between two electrodes on the same plane, a nonuniform electric field distribution is formed within the channel and the directionality and adaptability of the field is limited.…”

One-piece micropumps from liquid crystalline core-shell particles

“…In that respect, soft lithographic methods have easier process parameters, but to achieve a three-dimensional active device from the two-dimensional patterned elastomer layers, multi-layer structures have to be assembled. On the basis of this principle, a peristaltic micropump could be realized via a series of replica moulding from multiple templates 25 . In this contribution, we present the successful continuous fabrication of one-piece micropumps from a thermo-responsive LCE, which requires no elaborate micromachining techniques.…”