Apparatus and method for multiplex analysis
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 varying and/or maintaining a temperature of a reaction sample comprising:
(a) placing a chip in thermal contact with a heating element, wherein the chip comprises an array of micro wells for containing and confining a liquid reaction sample, said array comprising at least one open micro well having an open surface to be sealed;
(b) placing a transparent cover encompassing at least peripheral dimensions defining the open surface of the at least one open micro well to effect sealing of said micro well, wherein the transparent cover comprises an indium tin oxide heater;
(c) maintaining temperature of the indium tin oxide heater sufficiently higher relative to temperature of the heating element to prevent condensation of said liquid reaction sample; and
(d) applying a voltage to the heating element thereby varying and/or maintaining the temperature of the liquid reaction sample.
2. The method of claim 1 further comprising cycling the applying step to raise and lower the temperature of the liquid reaction sample.
3. The method of claim 1 , wherein the micro well has a dimension of about 10 mm to about 100 μm in length, about 100 mm to about 100 μm in width, and about 10 mm to about 100 μm in depth.
4. The method of claim 1 , wherein the micro well has a volume of from about 100 μl to about 0.001 μl.
5. The method of claim 1 , wherein the varying and/or maintaining of temperature is achieved by controlling the heating element alone without the aid of an external heat sink.
6. The method of claim 1 , wherein the micro well has an upper and a bottom surface, and wherein the heating element is attached to the bottom surface or the upper surface but not both.
7. The method of claim 1 , wherein the array of micro wells has a ramp temperature time of about 25 degrees C. or higher per second.
8. The method of claim 1 , wherein the indium tin oxide heater is an integral part of the transparent cover.
9. The method of claim 1 , wherein the micro well further comprises a plurality of grooves at the bottom surface.
10. The method of claim 1 , wherein the chip is in thermal contact with a temperature sensor.
11. The method of claim 1 , wherein the step of applying a voltage is effected by processing a predetermined algorithm stored on a computer readable media operatively linked to the heating element.
12. The method of claim 1 , wherein the transparent cover is made of a material selected from the group of glass, quartz, or silicon.
13. The method of claim 1 , further comprising the step of providing excitation wavelength to said micro well through said transparent cover.
14. The method of claim 13 , wherein the liquid reaction sample comprises reactants and products of a PCR reaction, wherein the products of said PCR reaction comprise amplified DNA templates.
15. The method of claim 14 , further comprising the step of collecting optical signals emitted from the reaction sample in said micro well, wherein the emitted optical signals are proportional to the amount of the products of said PCR reaction.
16. The method of claim 1 , wherein the transparent cover comprises a layer of adhesive encompassing at least the peripheral dimensions defining the open surface of the at least one open micro well.
17. The method of claim 16 , wherein the adhesive is made of a polymer.
18. The method of claim 1 , wherein the sealing of said micro well is airtight.