Electropipettor and compensation means for electrophoretic bias

• Main Authors: KNAPP; MICHAEL R, PARCE; J. WALLACE
• Format: Patent
• Language: English
• Published: 14.07.1998
• Edition: 6
• Subjects: BLASTING; CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; GENERATION; HEATING; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; LIGHTING; MEASURING; MECHANICAL ENGINEERING; MIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PHYSICS; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; TESTING; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

The present invention provides for techniques for transporting materials using electrokinetic forces through the channels of a microfluidic system. The materials are transported in slug regions of high ionic concentration, next to buffer material regions of high ionic concentration, which are separated by buffer 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.