Electropipettor and compensation means for electrophoretic bias
First Claim
1. A method of introducing materials from a plurality of sources into a microfluidic system, said microfluidic system having a capillary channel having an end, a voltage source for applying a voltage potential to an electrode in said microfluidic system, said method comprisingcontacting said capillary channel end to a subject material source;
- applying a voltage to said subject material source with respect to said electrode such that subject material from said source is electrokinetically introduced into said capillary channel toward said microfluidic system;
selecting a source of spacer material, said spacer material having a selected ionic concentration;
contacting said capillary channel end into said source of spacer material;
applying a voltage to said spacer material source with respect to said electrode such that said spacer material is electrokinetically introduced into said capillary channel next to said subject material; and
repeating the steps above with different material sources so that a plurality of different materials separated by spacer material is electrokinetically introduced into said capillary channel and transported toward said microfluidic system without intermixing said different materials.
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Abstract
The present invention provides for techniques for transporting materials using electrokinetic forces through the channels of a microfluidic system. The subject materials materials are transported in regions of high ionic concentration, next to spacer material regions of high ionic concentration, which are separated by spacer material regions of low ionic concentration. Such arrangements allow the materials to remain localized for the transport transit time to avoid mixing of the materials. Using these techniques, an electropipettor which is compatible with the microfluidic system is created so that materials can be easily introduced into the microfluidic system. The present invention also compensates for electrophoretic bias as materials are transported through the channels of the microfluidic system by splitting a channel into portions with positive and negative surface charges and a third electrode between the two portions, or by diffusion of the electrophoresing materials after transport along a channel.
596 Citations
11 Claims
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1. A method of introducing materials from a plurality of sources into a microfluidic system, said microfluidic system having a capillary channel having an end, a voltage source for applying a voltage potential to an electrode in said microfluidic system, said method comprising
contacting said capillary channel end to a subject material source; -
applying a voltage to said subject material source with respect to said electrode such that subject material from said source is electrokinetically introduced into said capillary channel toward said microfluidic system; selecting a source of spacer material, said spacer material having a selected ionic concentration; contacting said capillary channel end into said source of spacer material; applying a voltage to said spacer material source with respect to said electrode such that said spacer material is electrokinetically introduced into said capillary channel next to said subject material; and repeating the steps above with different material sources so that a plurality of different materials separated by spacer material is electrokinetically introduced into said capillary channel and transported toward said microfluidic system without intermixing said different materials. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of transporting fluid samples within a microfluidic channel, comprising:
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introducing at least a plug of a first fluid material having a first ionic strength into said channel; introducing at least a first sample fluid plug into said channel; introducing at least a second fluid material plug having said first ionic strength into said channel; introducing at least a third fluid material plug having a second ionic strength, said second ionic strength being lower than said first ionic strength; and applying a voltage across said channel. - View Dependent Claims (11)
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Specification