Porous semiconductor-based optical interferometric sensor

• US 6,248,539 B1
• Filed: 10/30/1997
• Issued: 06/19/2001
• Est. Priority Date: 09/05/1997
• Status: Expired due to Term

• Current Assignee: The Scripps Research Institute
• Original Assignee: The Scripps Research Institute, University of California San Diego (University of California)
• Inventors: Sailor, Michael J., Lin, Shang-Yi, Ghadiri, M. Reza, Dancil, Keiki-Pua S., Motesharei, Kianoush
• Primary Examiner(s): Chin, Christopher L.
• Application Number:
  US08/961,308
• Time in Patent Office: 1,328 Days
• Field of Search: 356/345, 356/352, 385/12, 385/129, 385/130, 422/82.05, 422/82.11, 435/287.1, 435/287.2, 435/288.7, 435/808, 435/973, 436/164, 436/165, 436/518, 436/527, 436/805
• US Class Current: 435/7.1
• CPC Class Codes: G01N 2021/458 using interferential sensor, e.g. sensor fibre, possibly on optical waveguide
• CPC Class Codes: G01N 21/45 using interferometric methods; using Schlieren methods
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: Y10S 435/808 Optical sensing apparatus
• CPC Class Codes: Y10S 435/973 Simultaneous determination of more than one analyte
• CPC Class Codes: Y10S 436/805 Optical property

Abstract

The measurement of the wavelength shifts in the reflectometric interference spectra of a porous semiconductor substrate such as silicon, make possible the highly sensitive detection, identification and quantification of small analyte molecules. The sensor of the subject invention is effective in detecting multiple layers of biomolecular interactions, termed “cascade sensing”, including sensitive detection of small molecule recognition events that take place relatively far from the semiconductor surface.

Claims

1. Means for detecting shifts in Fabry-Perot fringes with a solid state sensor, said fringes being reflected from a substrate, said means for detecting comprising a semiconductor substrate having a porous surface, said substrate surface further having a plurality of discrete and separate regions, and having an organic binder compound adsorbed thereon, said substrate having a thickness selected to generate Fabry-Perot fringes from reflection of light therefrom.

2. The detecting means of claim 1 further including an analyte that binds to said organic binder compound, said semiconductor substrate, when containing said analyte bound to said organic binder compound reflecting light to exhibit Fabry-Perot fringe wavelengths different from those exhibited when the analyte is not so bound.

3. A reflective sensor for an analyte having a layer of porous semiconductor with a plurality of discrete and separate sites having one or more binder compounds specific to the analyte, said layer being substantially transparent and having a top surface and a bottom surface which reflect light to exhibit Fabry-Perot fringes having a first set of characteristic wavelengths in the absence of analyte and second set of characteristic wavelengths when analyte is present, said second set of characteristic wavelengths being detectably shifted from said first set of characteristic wavelengths.

4. The detecting means of claim 3 wherein said layer of porous semiconductor with a binder compound specific to the analyte exhibits a first index of refraction, wherein said analyte exhibits a second index of refraction which is greater than said first index of refraction, but wherein the second set of characteristic wavelengths is shorter than the first set of characteristic wave lengths.

5. The detecting means of claim 4 wherein said semiconductor comprises silicon.

6. A means for detecting shifts in Fabry-Perot fringes for use in detecting a target species comprising a porous semiconductor layer with a plurality of discrete and separate regions having one or more binder compounds, of a thickness selected to generate Fabry-Perot fringes from the reflection of light therefrom, a binding material specific to the target species, said Fabry-Perot fringes having a first set of characteristics peak wavelengths in the absence of the target species and a second set of characteristic peak wavelengths in the presence of the target species with the second, set of peak wavelengths being shifted toward shorter wavelengths relative to said first set of wavelengths.

7. The detecting means of claim 6 wherein said semiconductor comprises silicon.

8. The detecting means of claim 7 wherein the porous silicon has a first index of refraction and said target species has a second index of refraction which is higher than said first index of refraction.

9. The detecting means of claim 8 additionally comprising a binder material specific to the porous silicon layer, said binder material specifically binding the target species.

10. A means for detecting a shift in Fabry-Perot fringes, including a reflective sensor array for at least one analyte, said array comprising a layer of porous semiconductor with a plurality of discrete and separate regions having one or more binder compounds specific to at least one of the at least one analyte, said layer being substantially transparent and having a top surface and a bottom surface which reflect light in each of the plurality of regions to exhibit Fabry-Perot fringes for such regions having a first set of characteristic wave lengths in the absence of the at least one analyte and a second set of characteristic wave lengths when analyte is present, said second set of characteristic wave lengths being detectably shifted from said first set of characteristic wavelengths.