Method for detecting biomolecules electrically and biochip therefor
The present invention relates to a method for detecting the presence and/or the reaction of a biomolecule by monitoring changes of electrical property accurately according to the biological, biochemical or chemical reaction of the biomolecule, and a biochip provided for this purpose.
1. A biochip for detecting a biomolecule electrically comprising:
a first plate that has a plurality of sensing electrodes;
a second plate that forms a space of a reaction chamber with respect to the first plate by being combined with the first plate in a predetermined distance; and
wherein the second plate forming the space of the reaction chamber is perforated to have a fluid inlet in the direction of thickness and further perforated to have a fluid outlet in the direction of thickness on the opposite side of the fluid inlet; the inlet and the reaction chamber, and the outlet and the reaction chamber are communicated with each other to allow fluid to flow therethrough in the reaction chamber; and a reference fluid having a high dielectric constant, a reaction solution and a target sample are introduced through the inlet, and the reference fluid having a high dielectric constant, the reaction solution and the target sample flow outside through the outlet.
2. The biochip as claimed in claim 1 , wherein an inlet micro channel that directs to introduce fluid into the inlet, and an outlet micro channel that directs to discharge fluid from the outlet are formed by layering a third plate on the second plate; the inlet micro channel is communicated with an injection opening into which the reference fluid having a high dielectric constant, the reaction solution and the target sample are injected and penetrates through the third plate; and the outlet micro channel is communicated with a discharge opening into which the reference fluid having a high dielectric constant, the reaction solution and the target sample are discharged and penetrates through the third plate.
3. The biochip as claimed in claim 2 , further comprising a valve structure that can control fluid injection into the space of the reaction chamber or fluid discharge from the space of the reaction chamber on the inlet micro channel or the outlet micro channel, respectively.
4. The biochip as claimed in claim 3 , wherein the valve structure is a passage extended after being penetrated into the third plate in the direction of thickness, between the injection opening and the space of the reaction chamber, or between the discharge opening and the space of the reaction chamber wherein oil is stored in said passage.
5. The biochip as claimed in claim 1 , wherein the third plate is made of PDMS (polydimethylsiloxane).
6. The biochip as claimed in claim 1 , wherein the biochip performs the following steps:
(a) first introducing the reference fluid having a high dielectric constant into the reaction chamber, and then first measuring an impedance value or a capacitance value between the sensing electrodes;
(b) removing the reference fluid having a high dielectric constant from the reaction chamber from step (a) and introducing the reaction solution and the target sample into the reaction chamber;
(c) reacting the target sample under the reaction solution in the reaction chamber as prepared in step (b);
(d) removing the reaction solution from the reaction chamber after step (c);
(e) secondly introducing said reference fluid having a high dielectric constant again into the reaction chamber, and then secondly measuring an impedance value or a capacitance value between the sensing electrodes; and
(f) comparing the impedance value or the capacitance value measured in the step (a) with the impedance value or the capacitance value measured in the step (e).
7. The biochip as claimed in claim 1 , wherein the reference fluid having a high dielectric constant has at least 4 of dielectric constant.
8. The biochip as claimed in claim 7 , wherein the reference fluid having a high dielectric constant is distilled water or deionized water.
9. The biochip as claimed in claim 1 , wherein the sensing electrodes are formed of interdigitated electrode.
10. The biochip as claimed in claim 9 , wherein each interval between the sensing electrodes is 1 to 4 μm.
11. The biochip as claimed in claim 1 , wherein the sensing electrode is bound with a receptor interacting with the biomolecule.
12. The biochip as claimed in claim 11 , wherein the receptor is a probe or a primer.