Biological and chemical microcavity resonant sensors and methods of detecting molecules
Resonant sensors and methods of detecting specific molecules with enhanced sensitivity. Optical energy is introduced into a microcavity, such as a silica toroid-shaped microcavity. The microcavity sensor has a functionalized outer surface and a sufficiently high Q value to generate an evanescent optical field with increased intensity. A molecule bound to the functionalized outer surface interacts with the external optical field, thereby heating the microcavity and generating a detectable resonant wavelength shift, which indicates a small number of molecules, even a single molecule, without the use of fluorescent or metal labels. Resonant sensors and methods can also be used to detect specific molecules, even a single molecule, within an environment. One application is detecting very small quantities or a single molecule of heavy water in ordinary water.
1. A method of detecting at least one molecule in an environment, comprising: introducing optical energy into a planar, non-spherical microcavity having a functionalized outer surface and being supported by a substrate, the substrate comprising a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of the planar, non-spherical microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the planar, non-spherical microcavity, and an outer edge of the planar, non-spherical microcavity extending outwardly beyond a top outer edge of the substrate; and detecting at least one unlabeled molecule bound to the functionalized outer surface based on a thermo-optic interaction between the at least one molecule and an evanescent field extending beyond an outer edge of the planar, non-spherical microcavity and into the environment.
2. The method of claim 1 , introducing optical energy further comprising coupling optical energy into a toroid-shaped microcavity from a waveguide.
3. The method of claim 1 , introducing optical energy further comprising coupling energy into a planar, non-spherical microcavity having a Q value greater than 10 6 .
4. The method of claim 1 , detecting the at least one unlabeled molecule bound to the functionalized outer surface based on the thermo-optic interaction resulting from the at least one unlabeled molecule binding to the functionalized outer surface, interacting with the evanescent field generated by optical energy circulating inside the planar, non-spherical microcavity and heating the planar, non-spherical microcavity, thereby causing a detectable shift of the wavelength of the optical energy resonating in the planar, non-spherical microcavity.
5. The method of claim 1 , detecting the at least one unlabeled molecule comprising detecting a single unlabeled molecule bound to the functionalized outer surface.
6. The method of claim 1 , wherein the environment is an aqueous environment.
7. A method of detecting at least one molecule in an environment, comprising: introducing optical energy into a planar, non-spherical silica microcavity having a functionalized outer surface and being supported by a substrate, the substrate comprising a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of the planar, non-spherical silica microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the planar, non-spherical silica microcavity, and an outer edge of the planar, non-spherical silica microcavity extending outwardly beyond a top outer edge of the substrate; and detecting at least one molecule bound to the functionalized outer surface based on a wavelength shift of the optical energy resonating in the planar, non-spherical silica microcavity.
8. The method of claim 7 , detecting at least one molecule further comprising detecting a single unlabeled molecule bound to the functionalized outer surface.
9. The method of claim 7 , introducing optical energy further comprising introducing optical energy into a toroid-shaped planar, non-spherical silica microcavity.
10. The method of claim 7 , detecting at least one molecule being based on a thermo-optic interaction resulting from the at least one molecule binding to the functionalized outer surface, interacting with the evanescent field generated by optical energy circulating inside the planar, non-spherical silica microcavity and heating the planar, non-spherical silica microcavity, thereby causing a detectable shift of the wavelength of the optical energy resonating in the planar, non-spherical silica microcavity.
11. The method of claim 7 , wherein the environment is an aqueous environment.
12. A method of detecting at least one molecule in an environment, comprising: introducing optical energy into an ultra-high Q planar, non-spherical microcavity having a Q value of at least 1×10 8 and a functionalized outer surface and being supported by a substrate, the substrate comprising a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of the ultra-high Q planar, non-spherical microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the ultra-high Q planar, non-spherical microcavity, and an outer edge of the ultra-high Q planar, non-spherical microcavity extending outwardly beyond a top, outer edge of the substrate; and detecting at least one molecule bound to the functionalized outer surface based on a wavelength shift of the optical energy resonating in the ultra-high Q planar, non-spherical microcavity.
13. The method of claim 12 , detecting at least one molecule comprising detecting a single unlabeled molecule bound to the functionalized outer surface.
14. The method of claim 12 , introducing optical energy further comprising introducing optical energy into a toroid-shaped ultra-high Q planar, non-spherical microcavity.
15. The method of claim 12 , detecting the at least one molecule being based on a thermo-optic interaction resulting from the at least one molecule binding to the functionalized outer surface, interacting with the evanescent field generated by optical energy circulating inside the ultra-high Q planar, non-spherical microcavity and heating the ultra-high Q planar, non-spherical microcavity, thereby causing a detectable shift of the wavelength of the optical energy resonating in the ultra-high Q planar, non-spherical microcavity.
16. The method of claim 12 , wherein the environment is an aqueous environment.
17. A resonant sensor for detecting at least one molecule in an environment, comprising: a planar, non-spherical silica microcavity having a functionalized outer surface and being supported by a substrate, the substrate comprising a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of the planar, non-spherical silica microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the planar, non-spherical silica microcavity; and a waveguide positioned to couple optical energy into the planar, non-spherical silica microcavity, the planar, non-spherical silica microcavity having a sufficiently high Q value to allow detection of individual molecules bound to the functionalized outer surface based on a wavelength shift of the optical energy resonating in the planar, non-spherical silica microcavity.
18. The resonant sensor of claim 17 , wherein an outer edge of the planar, non-spherical silica microcavity extends outwardly beyond an outer top edge of the substrate.
19. The resonant sensor of claim 17 , wherein the planar, non-spherical silica microcavity has a toroid shape.
20. The resonant sensor of claim 17 , wherein the functionalized outer surface includes a chemically active substance or a biologically active substance.
21. The resonant sensor of claim 20 , wherein the functionalized outer surface includes an antibody or an antigen.
22. The resonant sensor of claim 20 , wherein the functionalized outer surface includes a protein.
23. The resonant sensor of claim 17 being adapted to detect a single unlabeled molecule.
24. The resonant sensor of claim 17 being adapted to detect individual molecules based on a thermo-optic interaction resulting from a molecule binding to the functionalized outer surface, interacting with the evanescent field generated by optical energy circulating inside the planar, non-spherical silica microcavity and heating the planar, non-spherical silica microcavity, thereby causing a detectable shift of the wavelength of the optical energy resonating in the planar, non-spherical silica microcavity.
25. The resonator sensor of claim 17 being adapted to operate in an aqueous environment.
26. The resonant sensor of claim 17 , wherein a plane defined by the planar, non-spherical silica microcavity and a plane defined by a top surface of the top portion of the substrate are substantially parallel.
27. The resonant sensor of claim 17 , wherein the substrate is silicon.
28. A resonant sensor for detecting at least one molecule in an environment, comprising: an ultra-high Q planar, non-spherical microcavity having a functionalized outer surface and a Q value greater than 1×10 8 ; a substrate supporting the ultra-high Q planar, non-spherical microcavity, the substrate comprising a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of the ultra-high Q planar, non-spherical microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the ultra-high Q planar, non-spherical microcavity; and a waveguide positioned to couple optical energy into the ultra-high Q planar, non-spherical microcavity, the ultra-high Q planar, non-spherical microcavity having a sufficiently high Q value to allow detection of individual molecules bound to the functionalized outer surface based on a shift of a wavelength of the optical energy resonating in the ultra-high Q planar, non-spherical microcavity.
29. The resonant sensor of claim 28 , wherein an outer edge of the ultra-high Q planar, non-spherical microcavity extends outwardly beyond an outer top edge of the substrate.
30. The resonant sensor of claim 28 , wherein the ultra-high Q planar, non-spherical microcavity has a toroid shape.
31. The resonant sensor of claim 28 being adapted to detect individual molecules based on a thermo-optic interaction resulting from a molecule binding to the functionalized outer surface, interacting with the evanescent field generated by optical energy circulating inside the ultra-high Q planar, non-spherical microcavity and heating the ultra-high Q planar, non-spherical microcavity, thereby causing a detectable shift of the wavelength of optical energy resonating in the ultra-high Q planar, non-spherical microcavity.
32. The resonator sensor of claim 28 being adapted to operate in an aqueous environment.
33. The resonant sensor of claim 29 , wherein a plane defined by the ultra-high Q planar, non-spherical microcavity and a plane defined by a top surface of the top portion of the substrate are substantially parallel.
34. The resonant sensor of claim 29 , wherein the ultra-high Q planar, non-spherical microcavity is silica and the substrate is silicon.
35. A resonant sensor for detecting at least one molecule in an environment, comprising: an ultra-high Q planar, non-spherical microcavity made of silica and having a functionalized outer surface, the microcavity having a Q value of at least 10 8 ; a substrate that supports the ultra-high Q planar, non-spherical microcavity made of silica, wherein the substrate is made a material other than silica and comprises a bottom portion, a top portion and a middle portion extending between the bottom portion and the top portion, the middle portion comprising a tapered or angled surface such that the bottom portion is wider than the top portion, an inner edge of ultra-high Q planar, non-spherical microcavity extending around an outer edge of the top portion of the substrate such that the substrate supports and elevates the ultra-high Q planar, non-spherical microcavity; and a waveguide positioned to couple optical energy into the ultra-high Q planar, non-spherical microcavity, the Q value of the ultra-high Q planar, non-spherical microcavity allowing detection of individual molecules bound to the functionalized outer surface based on a shift of a wavelength of the optical energy resonating in the ultra-high Q planar, non-spherical micro-cavity.
36. The resonant sensor of claim 35 , wherein an outer edge of the ultra-high Q planar non-spherical microcavity extends outwardly beyond an outer top edge of the substrate.
37. The resonant sensor of claim 35 , wherein a plane defined by the ultra-high Q planar, non-spherical microcavity and a plane defined by a top surface of the top portion of the substrate are substantially parallel.
38. The resonant sensor of claim 35 , wherein the substrate is silicon.