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Issue 12, 2005
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Continuous flow in open microfluidics using controlled evaporation

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This paper presents a method for programming the flow rate of liquids inside open microfluidic networks (MFNs). A MFN comprises a number of independent flow paths, each of which starts with an open filling port, has a sealed microchannel in which assays can be performed, and an open capillary pump (CP). The MFN is placed over Peltier elements and its flow paths initially fill owing to capillary forces when liquids are added to the filling ports. A cooling Peltier element underneath the filling ports dynamically prevents evaporation in all filling ports using the ambient temperature and relative humidity as inputs. Another Peltier element underneath the CPs heats the pumps thereby inducing evaporation in the CPs and setting the flow rate in the microchannels. This method achieves flow rates in the microchannels ranging from ∼1.2 nL s−1 to ∼30 pL s−1, and is able to keep 90% of a 0.6 µL solution placed in an open filling port for 60 min. This simple and efficient method should be applicable to numerous assays or chemical reactions that require small and precise flow of liquids and reagents inside microfluidics.

Graphical abstract: Continuous flow in open microfluidics using controlled evaporation

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Article information

14 Jul 2005
10 Oct 2005
First published
26 Oct 2005

Lab Chip, 2005,5, 1355-1359
Article type

Continuous flow in open microfluidics using controlled evaporation

M. Zimmermann, S. Bentley, H. Schmid, P. Hunziker and E. Delamarche, Lab Chip, 2005, 5, 1355
DOI: 10.1039/B510044E

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