Method and apparatus for sample injection in microfabricated devices

• US 20020168780A1
• Filed: 02/11/2002
• Published: 11/14/2002
• Est. Priority Date: 02/09/2001
• Status: Abandoned Application

• Current Assignee: Microchem Solutions
• Original Assignee: Microchem Solutions
• Inventors: Liu, Shaorong, Lu, Juan
• Application Number:
  US10/076,042
• Publication Number:
  US 20020168780A1
• Time in Patent Office: Days
• US Class Current: 436/180
• CPC Class Codes: B01D 61/28 Apparatus therefor
• CPC Class Codes: B01D 61/56 Electro-osmotic dewatering
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0421 electrophoretic flow
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/0622 distribution valves, valves having multiple inlets and/or outlets, e.g. metering valves, multi-way valves
• CPC Class Codes: B01L 2400/065 sliding valves
• CPC Class Codes: B01L 3/0241 Drop counters; Drop formers making arrays for combinatorial libraries B01J19/0046; automation of dispensing for analysis G01N35/10
• CPC Class Codes: B01L 3/0293 for liquids
• CPC Class Codes: B01L 3/5025 for parallel transport of multiple samples
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence
• CPC Class Codes: B81B 1/004 Through-holes, i.e. extending from one face to the other face of the wafer
• CPC Class Codes: B81B 2201/058 Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: G01N 2001/4016 being a selective membrane, e.g. dialysis or osmosis
• CPC Class Codes: G01N 2030/204 Linearly moving valves, e.g. sliding valves
• CPC Class Codes: G01N 2035/00158 Elements containing microarrays, i.e. "biochip"
• CPC Class Codes: G01N 2035/00247 : Microvalves
• CPC Class Codes: G01N 2035/1032 : Dilution or aliquotting
• CPC Class Codes: G01N 27/44743 : Introducing samples
• CPC Class Codes: G01N 27/44791 : Microapparatus sample containers with integrated microfluidic structures B01L3/5027
• CPC Class Codes: G01N 35/10 : Devices for transferring samples or any liquids to, in, or from, the analysis apparatus, e.g. suction devices, injection devices G01N35/0099 takes precedence
• CPC Class Codes: G01N 35/1016 : Control of the volume dispensed or introduced
• CPC Class Codes: Y10T 436/11 : Automated chemical analysis
• CPC Class Codes: Y10T 436/25 : including sample preparation
• CPC Class Codes: Y10T 436/25375 : Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]
• CPC Class Codes: Y10T 436/255 : including use of a solid sorbent, semipermeable membrane, or liquid extraction
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

An off-column sample injection scheme for introducing samples into micro-reaction channels in microfabricated devices. In one aspect of the present invention, off-column sample injection is effected by introducing sample from a sample reservoir provided on the substrate of the microfabricated device into a reaction channel via a constricted channel or opening interface, e.g., a narrow connection-channel and/or a pinhole. In another embodiment of the present invention, off-column sample injection is effected by introducing sample from a sample reservoir that is provided outside the substrate of the microfabricated device. A through-hole is provided in the substrate to facilitate sample introduction into the reaction channel. In a further aspect of the present invention, the free-end of a capillary tube connected to the sample-channel is moved alternatively to a sample and an auxiliary solution to bring multiple samples in series to the vicinity of a reaction channel for convenient sample introduction and high-throughput assays.

Claims

1. A microfluidic device for handling a sample, comprising:

a substrate;

a reaction channel defined on the substrate along which the sample migrates;

a sample channel defined on the substrate from which the sample is introduced into the reaction channel; and

a constricted conduit interface in fluid coupling between the reaction channel and sample channel, through which the sample is injected from the sample channel into the reaction channel.

2. A microfluidic device as in claim 1, wherein the constricted conduit comprises a relatively short and narrow channel in comparison to the sample channel.

3. A microfluidic device as in claim 1, wherein the constricted conduit comprises a constricted opening.

4. A microfluidic device as in claim 1, wherein the constricted opening is in the form of a pinhole.

5. A microfluidic device as in claim 1, wherein the constricted conduit is configured and sized to have at least one of the following characteristics:

prevent sample diffusion from the sample channel into the reaction channel, improve structural dimension control in fabrication, and reduce augmented electrophoretic mobility-based bias of sample from the sample channel.

6. A microfluidic device as in claim 1, wherein two ends of the sample channel are in fluid communication with a sample reservoir and a waste reservoir defined on the substrate, respectively.

7. A microfluidic device as in claim 1, wherein the sample channel is in fluid communication with a sample source external of the substrate.

8. A microfluidic device as in claim 7, wherein the sample channel takes the form of a through-hole provided in the substrate to facilitate introduction of sample into the reaction channel.

9. A microfluidic device as in claim 8, wherein the through-hole collects sample when sample is loaded on the through-hole from the external source.

10. A microfluidic system, comprising:

a substrate;

a reaction channel defined on the substrate along which the sample migrates;

a sample channel defined on the substrate from which the sample is introduced into the reaction channel;

a constricted conduit interface in fluid coupling between the reaction channel and sample channel, through which the sample is injected from the sample channel into the reaction channel;

a capillary tube having a first end depositing fluid on the sample-channel, and a second end coupled to at least one of a sample reservoir and an auxiliary buffer reservoir; and

means for delivering sample and buffer to the sample channel via said capillary tube from said at least one of a sample source and an auxiliary buffer reservoir.

11. A microfluidic system as in claim 10, wherein the second end of the capillary tube is supported to access multiple samples in series from multiple sample reservoirs.

12. A method for injecting sample into a reaction channel defined on the substrate of a microfluidic device, comprising the steps of:

defining on the substrate a sample channel from which the sample is introduced into the reaction channel;

defining a constricted conduit interface in fluid coupling between the reaction channel and sample channel, through which the sample is injected from the sample channel into the reaction channel; and

applying a driving force to injecting the sample from the sample channel into the reaction channel through the constricted conduit.