Electrostatic control of ionic environment in a droplet based platform for biological applications
A process and device for electrostatically controlling an ionic environment in a droplet, such as in a droplet-based platform including polymerase-chain reaction (PCR) applications. The process includes providing a chip that comprises at least a pair of electrodes, placing a salt-containing droplet on the chip, and then applying a bias across the electrodes to accumulate ions near surfaces of the electrodes, thereby depleting a bulk salt concentration in regions of the droplet away from the electrodes.
1. A device for controlling an ionic environment in a droplet, comprising:
a dielectric substrate;
a biological sensor mounted to the substrate;
and at least a pair of electrodes mounted to the substrate and electrically isolated from each other and from the sensor, the electrodes having a dentritic surface morphology;
wherein the biological sensor is disposed between the pair of electrodes.
2. The device of claim 1 , wherein the dentritic surface morphology is formed from Pt-black.
3. The device of claim 2 , wherein each electrode is independently controlled to apply a different voltage.
4. The device of claim 1 , further comprising a voltage source connected across the pair of electrodes, the voltage source configured to apply a voltage bias across the pair of electrodes to accumulate ions near surfaces of the electrodes when a droplet is placed on the sensor and the electrodes, thereby reducing the bulk salt concentration in regions of the droplet away from the electrodes.
5. The device of claim 4 , further comprising an electronic controller having a computer processor and a memory, the electronic controller operatively connected to the voltage source and the biological sensor, the electronic controller configured to control the applied voltage and monitor a signal output from the biological sensor.
6. The device of claim 1 , wherein the biological sensor is a DNA sensor.
7. The device of claim 6 , wherein the DNA sensor is coated with a receptor DNA material.
8. A device for controlling an ionic environment in a droplet, comprising:
a dielectric substrate;
a biological sensor mounted to the substrate; and
at least two electrodes mounted to the substrate, each electrode being electrically isolated from the other and electrically isolated from the sensor, and wherein:
at least one electrode has a dendritic surface morphology, and
the biological sensor is disposed between the electrodes.
9. The device of claim 8 , wherein the dendritic surface morphology is formed from Pt-black.
10. The device of claim 9 , further comprising independent voltage sources connected to each electrode, each voltage source configured to apply a voltage the corresponding electrode to accumulate, depending on the voltage polarity, positive or negative ions near surfaces of the electrodes when a droplet is placed on the sensor and the electrodes, thereby reducing the bulk salt concentration in regions of the droplet away from the electrodes.
11. The device of claim 10 , further comprising an electronic controller having a computer processor and a memory, the electronic controller operatively connected to the voltage source and the biological sensor, the electronic controller configured to control the applied voltage and monitor a signal output from the biological sensor.
12. The device of claim 8 , wherein the biological sensor is a DNA sensor.
13. The device of claim 12 , wherein the DNA sensor is coated with a receptor DNA material.
14. The device of claim 8 , wherein each electrode is independently controlled to apply voltage.