Methods and apparatus for measuring analytes
View Patent ↗Methods and apparatus relating to FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.
1. An apparatus comprising:
an array of sensors, a sensor of the array of sensors including an electrode structure in communication with an ion-sensitive field effect-transistor (ISFET);
a structure defining an array of reaction chambers, a reaction chamber of the array of reaction chambers having a sidewall surface and having a lower surface overlying the electrode structure of the sensor; and
a buffering inhibitor disposed on at least one of the sidewall surface or the lower surface of the reaction chamber.
2. The apparatus of claim 1 , wherein the buffering inhibitor includes a phospholipid.
3. The apparatus of claim 2 , wherein the phospholipid includes phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, or phosphatidylserine.
4. The apparatus of claim 1 , wherein the buffering inhibitor includes a sulfonic acid surfactant.
5. The apparatus of claim 4 , wherein the sulfonic acid surfactant includes poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether (PNSE), poly(styrenesulfonic acid), or a salt thereof.
6. The apparatus of claim 1 , wherein the buffering inhibitor includes poly(diallydimethylammonium), tetramethyl ammonium, or a salt thereof.
7. The apparatus of claim 1 , wherein the buffering inhibitor is covalently bound to the at least one of the sidewall surface or the lower surface of the reaction chamber.
8. The apparatus of claim 1 , wherein the buffering inhibitor is non-covalently bound to the at least one of the sidewall surface or the lower surface of the reaction chamber.
9. The apparatus of claim 1 , wherein the ion sensitive field effect transistor is responsive to pH.
10. The apparatus of claim 1 , wherein the ISFET communicates with the electrode through a floating gate.
11. The apparatus of claim 1 , wherein the ISFET defines a solid-state device.
12. The apparatus of claim 1 , further comprising a floating gate to communicate a charge between the electrode structure and the ISFET.