Light-based system for detecting analytes
View Patent ↗Device, kit and method of using same to detect analytes such as nucleic acids are described. An excitation source, preferably a nitride-based LED, emits light capable of being absorbed by luminophores. Sensors are stably attached, preferably via covalent or ionic bonds, to a surface within the device, such as the surface of the excitation source that is exposed to the sample. When a complex is formed between the sensors and the analyte, the luminophores emit light or emit light of a different wavelength, thereby signaling the presence or quantity of the analyte.
1. A device for detecting an analyte, comprising:
(a) an excitation source that emits light capable of being absorbed and emitted by a luminophore, and
(b) a sensor specific for the analyte that is attached directly or indirectly via a covalent or ionic bond to a surface of said excitation source, wherein said surface can be exposed to a sample.
2. The device of claim 1 , wherein the surface of the excitation source includes a coating or matrix to facilitate attachment of the sensor and the sensor is covalently or ionically attached to the coating or matrix.
3. The device of claim 2 , wherein the coating or matrix is a sputter-deposited coating of gold and the sensor is covalently attached thereto.
4. The device of claim 1 , wherein the surface of the excitation source is bare and the sensor is attached directly to the substrate material of the excitation source itself.
5. The device of claim 1 , wherein the surface of the excitation source is non-porous.
6. The device of claim 1 , wherein the surface of the excitation source has a surface area below 0.01 m 2 /g.
7. The device of claim 1 , wherein the surface of the excitation source is smooth and planar.
8. The device of claim 1 , wherein the sensor is attached to the bottom or interior of a channel(s) or trough(s) chat runs across the surface of the excitation source.
9. The device of claim 1 , wherein the excitation source is nitride-based.
10. The device of claim 9 , wherein the device has a flip-chip configuration in which the cladding layer(s) of the nitride-based excitation source are on a side of the nitride-based excitation source other than a side that is intended to be exposed to a sample.
11. The device of claim 10 , wherein the nitride-based excitation source is GaN-based.
12. The device of claim 11 , wherein the GaN-based excitation source is a GaN-based vertical cavity surface emitting laser diode.
13. The device of claim 11 , wherein the CaN-based excitation source is a GaN-based resonant cavity LED.
14. The device of claim 11 , wherein the CaN-based excitation source is a homoepitaxial GaN-based LED.
15. The device of claim 14 , wherein the homoepitaxial GaN-based LED comprises a light emitting semiconductor active region disposed on a substrate comprised of GaN having a dislocation density less than about 10 5 per cm 2 .
16. The device of claim 15 , wherein the homoepitaxial GaN-based LED comprises:
a) a n-electrode,
b) a n-GaN substrate,
c) a n-GaN or n-Al w Ga (1-w) N cladding layer,
d) an In x Ga (1-x) N active layer,
e) a p-Al y Ga (1-y) N cladding layer,
f) a p-GaN cladding layer, and
g) a p-electrode,
wherein 0≦x,y≦].
17. The device of claim 1 , wherein an array of sensors is attached via covalent or ionic bonds to the surface of the excitation source.
18. The device of claim 17 , wherein the sensors are isolated from each other on the surface of the excitation source by a grid comprised of an opaque material.
19. The device of claim 1 , wherein the light emitted by the excitation source is monochromatic.
20. The device of claim 19 , wherein the full width at half maximum of the emission spectrum of the excitation source is less than about ten percent of the peak wavelength.
21. The device of claim 1 , further comprising an optical filter.
22. The device of claim 21 , wherein the surface to which the sensor is bound is a surface on the optical filter.
23. The device of claim 1 , further comprising a photodetector.
24. The device of claim 23 , wherein the surface to which the sensor is bound is a surface on the photodetector.
25. The device of claim 1 , wherein the sensor comprises a nucleic acid.
26. The device of claim 25 , wherein the sensor comprises a single stranded nucleic acid that is bound to the surface via a thiol on the 5′ end of the sensor.
27. The device of claim 1 , further comprising a luminophore bound to the sensor prior to exposure to a sample.
28. The device of claim 1 , further comprising a luminophore tethered to the same surface as the sensor.
29. The device of claim 1 , wherein the device is capable of detecting the quantity of the analyte in a sample.