Stopped-flow, micro-fluidic device and method for the charge-based separation of complex analyte mixtures

A method for isoelectrically fractionating a sample of analytes, comprising:

• introducing the sample into a separation chamber zone through an inlet port situated on a first end of the micro-fluidic chamber;
• causing the sample to flow through part of the separation chamber zone and impact one or more flow path deflector elements situated proximate the inlet port and situated between the inlet port and a plurality of outlet ports, at least one of the one or more flow path deflector elements blocking a shortest path between the inlet port and at least one of the plurality of outlet ports, whereby the sample is redirected upon impacting the one or more path deflector elements;
• halting flow of the sample while the sample is in the separation chamber zone and isoelectrically fractionating the halted sample into a plurality of fractionated analyte groups;
• causing the plurality of fractionated analyte groups to flow through a remainder of the separation chamber zone and through a plurality of channels each leading from a different widthwise position in the separation chamber zone to one of the plurality of outlet ports;
• and
• causing the plurality of fractionated analyte groups to flow through the plurality of outlet ports, the plurality of outlet ports being situated at a second end of the micro-fluidic chamber substantially opposite the first end of the micro-fluidic chamber.

A micro-fluidic device for fractionating a sample of analytes according to their isoelectric points, the device comprising:

• a micro-fluidic chamber comprising one or more walls, a separation chamber zone contained within the one or more walls, and a fluid distribution chamber zone contained within the one or more walls and situated in such a way as to precede the separation chamber zone;
• an inlet port situated at a first end of the micro-fluidic chamber for passing a sample of analytes into the separation chamber zone;
• a plurality of outlet ports situated at a second end of the micro-fluidic chamber substantially opposite the first end, the plurality of outlet ports extending across a width that is equal to at least part of a width of the separation chamber zone;
• a plurality of channels each leading from a different widthwise position in the separation chamber zone to one of the plurality of outlet ports;
• a first flow path redirection element situated in the fluid distribution chamber zone proximate the inlet port and situated between the inlet port and the plurality of outlet ports, the first flow path redirection element blocking a shortest path between the inlet port and at least one of the plurality of outlet ports;
• and
• a plurality of additional flow path redirection elements situated in the fluid distribution chamber zone proximate the first flow path redirection element and situated between the first flow path redirection element and the plurality of outlet ports;
• wherein the first flow path redirection element and the plurality of additional flow path redirection elements are positioned in such a way as to substantially prevent lateral intermixing of a sample of analytes flowing through the separation chamber zone and out of the plurality of outlet ports.

A micro-fluidic device for fractionating a sample of analytes according to their isoelectric points, the device comprising:

• a pipette coupled to a micro-fluidic chamber comprising one or more walls and a separation chamber zone contained within the one or more walls;
• an inlet port situated at a first end of the micro-fluidic chamber for introducing a sample of analytes from the pipette into the separation chamber zone;
• a plurality of outlet ports situated at a second end of the micro-fluidic chamber substantially opposite the first end, the plurality of outlet ports extending across a width that is equal to at least part of a width of the separation chamber zone;
• a plurality of channels each leading from a different widthwise position in the separation chamber zone to one of the plurality of outlet ports;
• and
• one or more flow path deflector elements situated proximate the inlet port and situated between the inlet port and the plurality of outlet ports, at least one of the one or more flow path deflector elements blocking a shortest path between the inlet port and at least one of the plurality of outlet ports.

A method for isoelectrically fractionating a sample of analytes, comprising:

• causing a sample to flow through a plurality of first ports situated on a first end of a micro-fluidic chamber and into a separation chamber zone contained within the micro-fluidic chamber by applying a negative pressure at a second port situated at a second end of the micro-fluidic chamber that is substantially opposite the first end, whereby the sample is caused to flow in a first direction;
• halting flow of the sample once the sample is evenly distributed in the separation chamber zone and isoelectrically fractionating the halted sample into a plurality of fractionated analyte groups;
• and
• causing the plurality of fractionated analyte groups to flow through the separation chamber zone and out the plurality of first ports, whereby the plurality of fractionated analyte groups are caused to flow in a second direction substantially opposite the first direction.