Thermo-controllable chips for multiplex analyses
The present invention provides miniaturized instruments for conducting chemical reactions where control of the reaction temperature is desired or required. Specifically, this invention provides chips and optical systems for performing and monitoring temperature-dependent chemical reactions. The apparatus and methods embodied in the present invention are particularly useful for high-throughput and low-cost amplification of nucleic acids.
1. A method of performing a nucleic acid amplification reaction using a miniaturized nucleic acid amplification chip, said amplification involving a plurality of reaction samples and requiring cycling at least two temperature levels, comprising:
(a) providing a chip comprising an array of fluidically isolated micro wells, each of said micro wells is configured for receiving and confining a reaction sample, wherein the micro well is coated with a hydrophobic coating, and wherein the chip is placed in thermal contact with a heating element;
(b) dispensing the plurality of reaction samples into the fluidically isolated micro wells in ambient air that is saturated with moisture with respect to a planar surface of the chip using a dispenser under conditions to reduce evaporation of said reaction samples;
(c) controlling the heating element to effect cycling of the at least two temperature levels; and
(d) detecting optical signals coming from the reaction samples using an optical detection assembly, wherein the optical signals are indicative of the presence of amplified nucleic acids.
2. The method of claim 1 , wherein the controlling step comprises processing sensor signals retrieved from a temperature sensor operatively linked to a micro well based on a protocol stored on a computer readable medium.
3. The method of claim 1 , wherein the optical signals are proportional to the amount of the amplified nucleic acids.
4. The method of claim 1 , wherein the chip further comprises individually-controlled heating elements, each of which is operably coupled to a micro well of said array.
5. The method of claim 1 further comprising sealing a micro well by applying an adhesive layer over an open surface of the micro well.
6. The method of claim 5 further comprising applying a cover over the adhesive layer wherein the cover is transparent and comprises an ITO heater.
7. The method of claim 6 wherein the ITO heater heats the cover to a temperature greater than at least one of the two temperature levels.
8. The method of claim 1 wherein the chip has a ramp temperature time of about 25 degrees C. or higher.
9. The method of claim 1 wherein the plurality of reaction samples are dispensed into the micro wells while said micro wells are kept at about dew point temperature.
10. The method of claim 1 wherein the plurality of reaction samples are dispensed into the micro wells while said dispensing is carried out at temperatures no more than 1-5 degrees C. over dew point.
11. The method of claim 1 wherein the optical signal is a fluorescent signal.
12. The method of claim 1 wherein reaction samples comprise reagents necessary for said nucleic acid amplification reaction and a detectable label, wherein said detectable label generates said optical signal that is detected.
13. The method of claim 1 wherein said nucleic acid amplification reaction is polymerase chain reaction (PCR).
14. The method of claim 1 wherein the optical signals coming from the reaction samples are monitored during said nucleic acid amplification reaction.
15. The method of claim 1 wherein said nucleic acid amplification reaction is real-time polymerase chain reaction.
16. The method of claim 1 wherein the micro well has a volume of approximately 0.001 μl to 100 μl.
17. The method of claim 1 wherein the micro well has a volume of approximately 1 μl to 10 μl.
18. The method of claim 1 wherein the micro well has a dimension of approximately 100 μm to 10 mm in length by 100 μM to 10 mm in width.