Optothermally actuated capillary burst valve.

Johan Eriksen,Anders Kristensen,Rodolphe Marie,Brian Bilenberg

doi:10.1063/1.4979164

Johan Eriksen, Anders Kristensen + Show 2 more

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https://doi.org/10.1063/1.4979164

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Abstract

We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

Highlights

MATERIALS AND METHODSThe microfluidic device consists of microchannels defined at a single depth connecting capillary burst valves (Figure 1(a)) placed in parallel along the main channel (Figure 1(b)) accessible by Luer connectors
A silicon master is fabricated by UV photolithography followed by a deep reactive ion etch that defines the microfluidic structures with a depth of 31 μm
A nickel replica of the silicon master is made, and the devices were injection molded in cyclic olefin copolymer (COC) (Topas 5013, TOPAS Advanced Polymers, Inc.) using a melt temperature of 250 ◦C, shim temperature of 155 ◦C, peak pressure of 1155 bars, and a demolding temperature of 135 ◦C

Summary

Introduction

Thambrup et al have shown optically induced local heating using a near-infrared absorbing layer embedded in the lid of a microfluidic channel.10 Conveniently, the optothermal platform is based on an external laser so that the actuation of the capillary burst valve does not complicate the microfluidic system itself. The microfluidic device consists of microchannels defined at a single depth connecting capillary burst valves (Figure 1(a)) placed in parallel along the main channel (Figure 1(b)) accessible by Luer connectors.

Results

Conclusion