Microfluidic valve and method of making same
View Patent ↗The present technology provides for a microfluidic substrate configured to carry out PCR on a number of polynucleotide-containing samples in parallel. The substrate can be a single-layer substrate in a microfluidic cartridge. Also provided are a method of making a microfluidic cartridge comprising such a substrate. Still further disclosed are a microfluidic valve suitable for use in isolating a PCR chamber in a microfluidic substrate, and a method of making such a valve.
1. A method of making a micro fluidic valve, the method of making comprising:
directing a dispensing head over an inlet hole in a microfluidic substrate;
propelling a quantity of thermally responsive substance from the dispensing head into the inlet hole; and
maintaining a temperature of the microfluidic substrate so that the thermally responsive substance flows by capillary action from the inlet hole past a shoulder and into a microfluidic channel in communication with the inlet hole via the shoulder, wherein the shoulder is disposed between the inlet hole and the microfluidic channel.
2. The method of claim 1 , wherein the quantity is 75±15 nl.
3. The method of claim 1 , wherein the propelling utilizes compressed gas.
4. The method of claim 1 , wherein the thermally responsive substance is wax.
5. The method of claim 1 , wherein the shoulder is disposed at the bottom of the inlet hole.
6. The method of claim 1 , further comprising maintaining a temperature of the thermally responsive substance in the dispensing head so that the thermally responsive substance is dispensed in molten form into the inlet.
7. The method of claim 1 , wherein the volume of the microfluidic channel does not exceed a maximum volume of thermally responsive substance.
8. The method of claim 1 , wherein the directing is automatically controlled.
9. The method of claim 1 , wherein the quantity of thermally responsive substance is dispensed as a dot.
10. The method of claim 9 , wherein the dot has one dimension of around 100 μm.
11. The method of claim 1 , wherein the propelling utilizes heated air.
12. The method of claim 1 , wherein the dispensing head is heated.
13. The method of claim 1 , wherein microfluidic channel comprises a first end and a second end, and wherein the first end of the microfluidic channel is fluidly connected with the inlet hole.
14. The method of claim 1 , wherein microfluidic channel comprises a first end and a second end, and wherein the second end of the micro fluidic channel intersects a flow channel.
15. The method of claim 14 , wherein the intersection of the mlcrofluidic channel and the flow channel forms a T-junction which gives rise to lower capillary forces than in the microfluidic channel.
16. The method of claim 15 , wherein the flow of the thermally responsive substance stops when the thermally responsive substance reaches the flow channel.
17. A microfluidic valve made by the method of claim 1 .
18. A microfluidic substrate comprising one or more microfluidic valves made by the method of claim 1 .