Microfluidic devices for the controlled manipulation of small volumes

A method of forming and transporting a series of minute volume segments of a material in a microchannel comprising the steps of:

• a. providing a microchannel device having a first channel having an inlet end for receiving a transport fluid and an outlet end, and having a second channel having an inlet end for receiving a segmenting fluid and an outlet end interconnected with the first channel, the first channel having a substantially uniform surface composition;
• b. introducing a volume of segmenting fluid into the first channel through the second channel;
• c. transporting the volume of segmenting fluid in the first channel toward the first channel outlet end;
• and then
• d. repeating steps b. and c. to form a series of discrete volumes of the segmenting fluid,
• wherein the microchannel device comprises at least two electrical contacts in the first channel at a location between the outlet ends of the first channel and the second channel;
• and
• wherein the step of introducing the volume of the segmenting fluid into the first channel comprises applying a first electrical potential between two of the electrical contacts, the first electrical potential having magnitude and polarity that are effective for inducing flow of the transport fluid in the first channel.

An apparatus for forming and transporting a series of minute volume segments of a material comprising:

• a substrate having first and second microchannels formed therein, the first microchannel having an inlet end for connection to a source of transport fluid and an outlet end, the second microchannel having an inlet end for connection to a source of segmenting fluid and an outlet end interconnected with the first microchannel, the first microchannel having a substantially uniform surface composition;
• a third channel having an inlet end connected to a source of material and an outlet end interconnected with the first channel;
• a fourth channel having an inlet end interconnected with the first channel and comprising means for applying a motive force between the fourth channel and the third channel for inserting the volume of the material;
• means for applying a motive force to (i) introduce a volume of the segmenting fluid into the first microchannel, (ii) stop the introduction of the segmenting fluid volume in the first microchannel, and then (iii) transport the volume of the segmenting fluid in the first microchannel toward the first channel outlet end;
• and
• means for inserting a volume of the material between a pair of volumes of the segmenting fluid in the first channel.

An apparatus for forming and transporting a series of minute volume segments of a material comprising:

• a substrate having first and second microchannels formed therein, the first microchannel having an inlet end for connection to a source of transport fluid and an outlet end, the second microchannel having an inlet end for connection to a source of segmenting fluid and an outlet end interconnected with the first microchannel, the first microchannel having a substantially uniform surface composition;
• means for applying a motive force to (i) introduce a volume of the segmenting fluid into the first microchannel, (ii) stop the introduction of the segmenting fluid volume in the first microchannel, and then (iii) transport the volume of the segmenting fluid in the first microchannel toward the first channel outlet end;
• and
• means for selecting the material according to a quality or characteristic of the material and means for inserting the selected material between a pair of sequential volumes of the segmenting fluid in the first channel.

A method of forming and transporting a series of minute volume segments of a material in a microchannel comprising the steps of:

• a. providing a microchannel device having a first channel having an inlet end for receiving a transport fluid and an outlet end, and having a second channel having an inlet end for receiving a segmenting fluid and an outlet end interconnected with the first channel;
• b. introducing a user selectable volume of segmenting fluid into the first channel through the second channel;
• c. transporting the volume of segmenting fluid in the first channel toward the first channel outlet end;
• and then
• d. repeating steps b. and c. to form a series of discrete volumes of the segmenting fluid,
• wherein the microchannel device comprises at least two electrical contacts in the first channel at a location between the outlet ends of the first channel and the second channel;
• and
• wherein the step of introducing the volume of the segmenting fluid into the first channel comprises applying a first electrical potential between two of the electrical contacts, the first electrical potential having magnitude and polarity that are effective for inducing flow of the transport fluid in the first channel.

An apparatus for forming and transporting a series of minute volume segments of a material comprising:

• a substrate having first and second microchannels formed therein, the first microchannel having an inlet end for connection to a source of transport fluid and an outlet end, the second microchannel having an inlet end for connection to a source of segmenting fluid and an outlet end interconnected with the first microchannel;
• a third channel having an inlet end connected to a source of material and an outlet end interconnected with the first channel;
• a fourth channel having an inlet end interconnected with the first channel and comprising means for applying a motive force between the fourth channel and the third channel for inserting the volume of the material;
• means for applying a motive force to (i) introduce a user selectable volume of the segmenting fluid into the first microchannel, (ii) stop the introduction of the segmenting fluid volume in the first microchannel, and then (iii) transport the volume of the segmenting fluid in the first microchannel toward the first channel outlet end;
• and
• means for inserting a volume of the material between a pair of volumes of the segmenting fluid in the first channel.

An apparatus for forming and transporting a series of minute volume segments of a material comprising:

• a substrate having first and second microchannels formed therein, the first microchannel having an inlet end for connection to a source of transport fluid and an outlet end, the second microchannel having an inlet end for connection to a source of segmenting fluid and an outlet end interconnected with the first microchannel;
• means for applying a motive force to (i) introduce a user selectable volume of the segmenting fluid into the first microchannel, (ii) stop the introduction of the segmenting fluid volume in the first microchannel, and then (iii) transport the volume of the segmenting fluid in the first microchannel toward the first channel outlet end;
• and
• means for selecting the material according to a quality or characteristic of the material and means for inserting the selected material between a pair of sequential volumes of the segmenting fluid in the first channel.