초록 ▼

A microfluidic detection device provides reduced dispersion of axial concentration gradients in a flowing sample. The microfluidic detection device includes a cell body and a flow path through the cell body. The flow path has an inlet segment, an outlet segment, and a central segment, which forms a

A microfluidic detection device provides reduced dispersion of axial concentration gradients in a flowing sample. The microfluidic detection device includes a cell body and a flow path through the cell body. The flow path has an inlet segment, an outlet segment, and a central segment, which forms a detection cell. The central segment is located between and at an angle with both the inlet segment and the outlet segment. The central segment has a first junction with the inlet segment and a second junction with the outlet segment. The cell body contains two arms that can transmit light to and from the detection cell. At least a portion of a first arm is located in the first junction and at least a portion of a second arm is located in the second junction. The portions of the arms located in the junctions are situated so that fluid entering or exiting the central segment of the flow path flows around the outer surface of one of the portions. By ensuring that the flow velocity is high near the walls both at the beginning and at the end of the conduit, the configuration serves to counteract dispersion caused by the normal parabolic velocity profile of flow through a cylindrical conduit, where the fluid velocity is highest at the center. In addition, the configuration promotes efficient sweeping of the entire volume between the two arms. A method for manufacturing the microfluidic detection device is also provided.

대표청구항 ▼

The invention claimed is: 1. A method of making a microfluidic detection device comprising: (a) a cell body; (b) a flow path through the cell body, the flow path comprising: (i) an inlet segment having a first longitudinal axis; (ii) an outlet segment having a second longitudinal axis; and (iii) a

The invention claimed is: 1. A method of making a microfluidic detection device comprising: (a) a cell body; (b) a flow path through the cell body, the flow path comprising: (i) an inlet segment having a first longitudinal axis; (ii) an outlet segment having a second longitudinal axis; and (iii) a central segment located between the inlet segment and the outlet segment and in fluid communication with both the inlet segment and the outlet segment, the central segment having an inner surface; wherein the central segment has a first junction with the inlet segment and a second junction with the outlet segment and wherein the central segment has a third longitudinal axis, the third longitudinal axis being transverse to the first longitudinal axis and the second longitudinal axis; (c) a first optical fiber having a portion located in the first junction so that a first substantially annular region is formed between the first optical fiber and the inner surface of the central segment, wherein the first optical fiber has a diameter and the first annular region has a length that is approximately between 1-40 times the diameter of the first optical fiber; and (d) a second optical fiber having a portion located in the second junction so that a second substantially annular region is formed between the second optical fiber and the inner surface of the central segment, wherein the second optical fiber has a diameter and the second annular region has a length that is approximately between 1-40 times the diameter of the second optical fiber; wherein the portions of the optical fibers located in the junctions are situated so that fluid entering or exiting the central segment of the flow path flows through one of the annular regions; the method comprising the steps of: (a) coating a first surface of a first and second fused silica wafer with a layer of silicon; (b) transferring a microconduit pattern into the silicon layer on each wafer; (c) transferring the microconduit pattern from the silicon layer to the first surface of each wafer so that the first surface of each silica wafer has the pattern; (d) removing the layer of silicon from each wafer; (e) cleaning the first and the second wafer with both acid and base baths so that the first surface of each wafer is hydrophilic; (f) cleaning the first and second wafers megasonically so that the surfaces of the wafers are more hydrophilic; (g) bringing into contact the first surface of each wafer so that the first surfaces are substantially aligned and form conduits; (h) heating the first and second wafers so that the first and second wafers bond together; (i) filling the flow path with a sacrificial material; (j) dicing the bonded first and second wafers into one or more microfluidic devices; (k) removing the sacrificial material; (l) inserting the first optical fiber into the central segment so that at least a portion of the first optical fiber is located in the first junction; (m) adhering the first optical fiber to the central segment; (n) inserting the second optical fiber into the central segment so that at least a portion of the second optical fiber is located in the second junction; and (o) adhering the second optical fiber to the central segment. 2. A method of making a composite ceramic wafer which can be diced to provide a plurality of cell bodies for microfluidic detection devices, each of the cell bodies (1) being composed of ceramic material, (2) having a flow path therethrough, the flow path comprising (i) an inlet conduit having a first longitudinal axis; (ii) an outlet conduit having a second longitudinal axis; and (iii) a central conduit (a) having a third longitudinal axis transverse to the first longitudinal axis and to the second longitudinal axis, (b) being located between the inlet channel and the outlet channel and communicating with the inlet and outlet conduits, and (c) forming a first junction with the inlet conduit and a second junction with the outlet conduit, (3) including a first arm conduit in which a first arm can be secured so that a first substantially annular region is formed between the first arm and the inner surface of the central conduit, (4) including a second arm conduit in which a second arm can be secured so that a second substantially annular region is formed between the second arm and the inner surface of the central conduit, whereby fluid entering the central conduit flows through one of the annular regions and fluid exiting the central conduit flows through the other annular region; the method comprising the steps of (A) providing a first ceramic wafer having a first mating surface which has a first pattern etched thereon, the first pattern comprising first open channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (B) providing a second ceramic wafer having a second mating surface which has a second pattern etched thereon, the second pattern comprising second open channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (C) bonding the first and second mating surfaces together so that the first and second open channels together provide the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies. 3. A method according to claim 2 wherein each of the ceramic wafers is a silica wafer. 4. A method according to claim 2 wherein, before step (C), the mating surface of each of the wafers is treated by a method comprising the steps of (i) cleaning the mating surface with acid and base baths; and (ii) cleaning the mating surface megasonically. 5. A method according to claim 2 wherein step (C) comprises heating the first and second wafers so that the first and second wafers bond together. 6. A method according to claim 2 wherein each of the wafers is a silica wafer, and step (C) comprises heating the first and second wafers at a temperature of approximately 1165�� C. for 4-8 hours so that the interface between the first and second wafers essentially disappears. 7. A method of making a composite ceramic wafer which can be diced to provide a plurality of cell bodies for microfluidic detection devices, each of the cell bodies (1) being composed of ceramic material, (2) having a flow path therethrough, the flow path comprising (i) an inlet conduit having a first longitudinal axis; (ii) an outlet conduit having a second longitudinal axis; and (iii) a central conduit (a) having a third longitudinal axis transverse to the first longitudinal axis and to the second longitudinal axis, (b) being located between the inlet channel and the outlet channel and communicating with the inlet and outlet conduits, and (c) forming a first junction with the inlet conduit and a second junction with the outlet conduit, (3) including a first arm conduit in which a first arm can be secured so that a first substantially annular region is formed between the first arm and the inner surface of the central conduit, (4) including a second arm conduit in which a second arm can be secured so that a second substantially annular region is formed between the second arm and the inner surface of the central conduit, whereby fluid entering the central conduit flows through one of the annular regions and fluid exiting the central conduit flows through the other annular region; the method comprising the steps of (A) etching a first mating surface of a first ceramic wafer with a first pattern, the first pattern comprising first open channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (B) etching a second mating surface of a second ceramic wafer with a second pattern, the second pattern comprising second open channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (C) bonding the first and second mating surfaces together so that the first and second open channels together provide the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies. 8. A method according to claim 7 wherein each of the ceramic wafers is a silica, glass or quartz wafer. 9. A method according to claim 7 wherein each of the first and second wafers is a silica wafer; during step (A), the first mating surface has a coating of amorphous silicon thereon; and during step (B), the second mating surface has a coating of amorphous silicon thereon. 10. A method according to claim 9 wherein the layer of silicon is removed from each of the etched mating surfaces before step (C). 11. A method according to claim 9 wherein, after steps (A) and (B), and before step (C), the mating surface of each of the wafers is treated by a method comprising the steps of (i) cleaning the mating surface with acid and base baths; and (ii) cleaning the mating surface megasonically. 12. A method according to claim 7 wherein step (C) comprises heating the first and second wafers so that the first and second wafers bond together. 13. A method according to claim 7 wherein each of the wafers is a silica wafer, and step (C) comprises heating the first and second wafers at a temperature of approximately 1165�� C. for 4-8 hours so that the interface between the first and second wafers essentially disappears. 14. A method of making a plurality of cell bodies for microfluidic detection devices, each of the cell bodies (1) being composed of ceramic material, (2) having a flow path therethrough, the flow path comprising (i) an inlet conduit having a first longitudinal axis; (ii) an outlet conduit having a second longitudinal axis; and (iii) a central conduit (a) having a third longitudinal axis transverse to the first longitudinal axis and to the second longitudinal axis, (b) being located between the inlet channel and the outlet channel and communicating with the inlet and outlet conduits, and (c) forming a first junction with the inlet conduit and a second junction with the outlet conduit, (3) including a first arm conduit in which a first arm can be secured so that a first substantially annular region is formed between the first arm and the inner surface of the central conduit, (4) including a second arm conduit in which a second arm can be secured so that a second substantially annular region is formed between the second arm and the inner surface of the central conduit, whereby fluid entering the central conduit flows through one of the annular regions and fluid exiting the central conduit flows through the other annular region; the method comprising dicing a composite wafer which comprises (A) a first ceramic wafer having a first mating surface which has a first pattern etched thereon, the first pattern comprising first channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (B) a second ceramic wafer having a second mating surface which has a second pattern etched thereon, the second pattern comprising second channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; the first and second mating surfaces being bonded together so that the first and second open channels together provide the inlet, outlet, central, first arm and second arm conduits of the plurality of cell bodies. 15. A method according to claim 14 wherein the conduits in the composite wafer contain a sacrificial material, and the sacrificial material is removed after the composite wafer has been diced. 16. A method according to claim 14 which comprises, after dicing the composite wafer into cell bodies, securing first and second arms in the first and second arm conduits of the cell bodies. 17. A method according to claim 16 wherein the first and second arms are optical fibers. 18. A method according to claim 14 which comprises, after dicing the composite wafer into cell bodies, securing an inlet capillary in the inlet conduit and an outlet capillary in the outlet conduit. 19. A composite wafer which can be diced into a plurality of cell bodies for microfluidic detection devices, each of the cell bodies (1) being composed of ceramic material, (2) including (i) an inlet conduit having a first longitudinal axis; (ii) an outlet conduit having a second longitudinal axis; and (iii) a central conduit (a) having a third longitudinal axis transverse to the first longitudinal axis and to the second longitudinal axis, (b) being located between the inlet channel and the outlet channel and communicating with the inlet and outlet conduits, and (c) forming a first junction with the inlet conduit and a second junction with the outlet conduit, (iv) a first arm conduit in which a first arm can be secured so that a first substantially annular region is formed between the first arm and the inner surface of the central conduit, (v) a second arm conduit in which a second arm can be secured so that a second substantially annular region is formed between the second arm and the inner surface of the central conduit, whereby fluid entering the central conduit flows through one of the annular regions and fluid exiting the central conduit flows through the other annular region; the composite wafer comprising (A) a first ceramic wafer having a first mating surface which has a first pattern etched thereon, the first pattern comprising first channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; (B) a second ceramic wafer having a second mating surface which has a second pattern etched thereon, the second pattern comprising second channels corresponding to the inlet, outlet, central, first arm and second arm conduits of a plurality of cell bodies; the first and second mating surfaces being bonded together so that the first and second open channels together provide the inlet, outlet, central, first arm and second arm conduits of the plurality of cell bodies. 20. A composite wafer according to claim 19 wherein each of the ceramic wafers is a silica wafer.