Microfluidic devices to extract, concentrate and isolate molecules

A device to capture molecules from a fluid, comprising:

• a substrate formed of a material that is electrically insulating;
• a microfluidic channel made of an electrically insulating material formed on the substrate to carry a biofluid containing molecules including nucleic acids;
• an array of electrodes formed on the surface along a parallel direction of the microfluidic channel constituting a capture region, wherein the array of electrodes are operable to produce an electric field across the microfluidic channel that creates an electrostatic attractive force on the nucleic acids to immobilize them in the capture region;
• and
• a chamber formed on the substrate of the electrically insulating material and connected to the microfluidic channel, the chamber configured to have a volume less than that of the microfluidic channel and to collect nucleic acids that are released from immobilization in the capture region, wherein the microfluidic channel in the capture region is configured as a spiral-shaped channel.

A device to capture biomolecules from a fluid, comprising:

• a substrate formed of a material that is electrically insulating;
• a microfluidic channel made of an electrically insulating material and formed on the substrate to carry an electrolytic fluid containing biomolecules including nucleic acids and charged particles configured to bind the nucleic acids to a charged surface;
• a first chamber region formed in the microfluidic channel, the first chamber region structured to receive the electrolytic fluid containing the nucleic acids attached to the charged particles;
• a second chamber region in the microfluidic channel connected to the first chamber region and including one or more outlets to remove at least some of the electrolytic fluid, wherein the second chamber region is configured to have a volume less than that of the first chamber region;
• and
• a filter region in the microfluidic channel between the first chamber region and the second chamber region and structured to include holes of a size preventing the particles to pass but allowing the nucleic acids to pass through to the second chamber region,
• wherein, when the nucleic acids are released from attachment to the charged particles in the filter region, the released nucleic acids are collected in the second chamber region.

A device to capture biomolecules from a fluid, comprising:

• a substrate formed of a material that is electrically insulating;
• a microfluidic channel made of an electrically insulating material and formed on the substrate to carry an electrolytic fluid containing biomolecules including nucleic acids;
• a first chamber formed in the microfluidic channel and structured to include two or more regions separated by a porous membrane pre-coated with charged particles configured to bind the nucleic acids to a charged surface, wherein the porous membrane includes a plurality of holes of a size greater than that of the nucleic acids to allow them to pass through the porous membrane and smaller than the charged particles to prevent them to pass through the porous membrane;
• a second chamber in the microfluidic channel connected to the first chamber and including one or more outlets to remove at least some of the electrolytic fluid;
• a first control valve positioned in the microfluidic between the first chamber and the second chamber to control the flow of the electrolytic fluid between the first and second chambers;
• and
• a second control valve positioned in the microfluidic between the second chamber and the one or more outlets to control the flow of the electrolytic fluid out of the device,
• wherein, when the nucleic acids are released from attachment to the charged particles in a filter region, the released nucleic acids are collected in the second chamber.