Method for increasing sensor resolution by spectrally stacking responsive dyes

• US 10,845,305 B1
• Filed: 11/20/2015
• Issued: 11/24/2020
• Est. Priority Date: 11/20/2015
• Status: Active Grant

• Current Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Original Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Inventors: Ruckh, Timothy Tordella, Wang, Zhan
• Primary Examiner(s): Lam, Ann Y
• Application Number:
  US14/948,154
• Time in Patent Office: 1,831 Days
• CPC Class Codes: G01N 2021/6432 Quenching
• CPC Class Codes: G01N 2021/6439 with indicators, stains, dyes, tags, labels, marks
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 21/80 Indicating pH value
• CPC Class Codes: G01N 2201/061 Sources

Abstract

An analyte-sensitive substance is provided that has an optical property related to the concentration of an analyte. The analyte-sensitive substance includes an ionophore or other substance configured to provide a local pH, within the analyte-sensitive substance, that is related to the concentration of the analyte proximate the analyte-sensitive substance. The analyte-sensitive substance further includes a pH-sensitive fluorophore that increases or decreases its intrinsic fluorescence intensity with the local pH across a specified range of pH values. The analyte-sensitive substance further includes a pH-sensitive quencher configured to increase the slope of the change of fluorescence intensity of the pH-sensitive fluorophore across the specified range of pH values. The analyte-sensitive substance may further include an ionic additive configured to adjust the local pH such that the specified range of pH values corresponds to a range of analyte concentration values of interest.

Claims

1. A sensor comprising:

an analyte-sensitive substance, wherein the analyte-sensitive substance comprises;

an ionophore, wherein the ionophore is configured to provide a local pH within the analyte-sensitive substance related to a concentration of an analyte proximate the analyte-sensitive substance;

a pH-sensitive fluorophore, wherein the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases or decreases as a function of the local pH over a range of pH values according to an intrinsic intensity function; and

a pH-sensitive quencher, wherein the pH-sensitive quencher is configured to quench the pH-sensitive fluorophore via Forster resonance energy transfer to an extent that increases or decreases as a function of the local pH within the range of pH values, such that the pH-sensitive fluorophore in combination with the pH-sensitive quencher is configured to fluoresce with a fluorescence intensity that increases or decreases as a function of the local pH over the range of pH values according to a quencher-modified intensity function that exhibits an increased rate of change of fluorescence intensity over the range of pH values relative to the intrinsic intensity function of the pH-sensitive fluorophore.

2. The sensor of claim 1, further comprising:

a light emitter, wherein the light emitter is configured to illuminate the analyte-sensitive substance such that the pH-sensitive fluorophore is excited; and

a light sensor, wherein the light sensor is configured to detect light emitted from the analyte-sensitive substance responsive to the analyte-sensitive substance being illuminated by the light emitter.

3. The sensor of claim 1, wherein the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that decreases as a function of the local pH over the range of pH values, and wherein the quencher is configured to quench the pH-sensitive fluorophore to an extent that increases as a function of the local pH within the range of pH values.

4. The sensor of claim 1, wherein the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases as a function of the local pH over the range of pH values, and wherein the quencher is configured to quench the pH-sensitive fluorophore to an extent that decreases as a function of the local pH within the range of pH values.

5. The sensor of claim 1, wherein the analyte-sensitive substance further comprises:

an ionic additive, wherein the ionic additive comprises one of an anionic additive or a cationic additive, wherein the ionic additive is configured to one of raise or lower the local pH, and wherein an amount of the ionic additive in the analyte-sensitive substance is specified such that a presence of the analyte proximate the analyte-sensitive substance within a specified range of concentrations results in the local pH having a value within the range of pH values.

6. The sensor of claim 5, further comprising a plurality of nanoparticles, wherein each nanoparticle of the plurality of nanoparticles comprises an enclosing layer composed of an amphiphilic compound and the enclosing layer encloses the pH-sensitive fluorophore, the pH-sensitive quencher, and the ionic additive.

7. The sensor of claim 1, further comprising a plurality of nanoparticles, wherein each nanoparticle of the plurality of nanoparticles comprises an enclosing layer composed of an amphiphilic compound and the enclosing layer encloses the pH-sensitive fluorophore and the pH-sensitive quencher.

8. The sensor of claim 7, wherein the analyte-sensitive substance further comprises an analyte-permeable polymer, wherein the plurality of nanoparticles are disposed within the analyte-permeable polymer.

9. The sensor of claim 1, wherein the analyte-sensitive substance further comprises:

a further pH-sensitive fluorophore, wherein the further pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases or decreases as a function of the local pH over the range of pH values according to a further intrinsic intensity function, and wherein either (i) the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that decreases as a function of the local pH over the range of pH values and the further pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases as a function of the local pH over the range of pH values, or (ii) the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases as a function of the local pH over the range of pH values and the further pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that decreases as a function of the local pH over the range of pH values.

10. A sensor comprising:

an analyte-sensitive substance, wherein the analyte-sensitive substance comprises;

an ionophore, wherein the ionophore is configured to provide a local pH within the analyte-sensitive substance related to a concentration of an analyte proximate the analyte-sensitive substance;

a pH-sensitive fluorophore, wherein the pH-sensitive fluorophore is configured to fluoresce with a fluorescence intensity that increases or decreases as a function of the local pH over a range of pH values according to an intrinsic intensity function; and

an ionic additive, wherein the ionic additive comprises one of an anionic additive or a cationic additive, wherein the ionic additive is configured to only one of raise or lower the local pH, and wherein an amount of the ionic additive in the analyte-sensitive substance is specified such that a presence of the analyte proximate the analyte-sensitive substance within a specified range of concentrations results in the local pH having a value within the range of pH values.

11. The sensor of claim 10, further comprising a plurality of nanoparticles, wherein each nanoparticle of the plurality of nanoparticles comprises an enclosing layer composed of an amphiphilic compound, and wherein the pH-sensitive fluorophore and the ionic additive are disposed within respective enclosing layers of individual nanoparticles of the plurality of nanoparticles.

12. The sensor of claim 10, further comprising:

a light emitter, wherein the light emitter is configured to illuminate the analyte-sensitive substance such that the pH-sensitive fluorophore is excited; and

a light sensor, wherein the light sensor is configured to detect light emitted from the analyte-sensitive substance responsive to the analyte-sensitive substance being illuminated by the light emitter.