# US 2017/0281065 A1 · System and method for monitoring nitric oxide levels using a non-invasive, multi-band biosensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0281065 A1 - Document ID: US20170281065A1 - Status: Published application - Kind: A1 - Application number: 15/622,941 - Filed: 2017-06-14 - Published: 2017-10-05 - Earliest claimed: 2015-09-25 - Assignees: Sanmina Corporation - Applicants: Sanmina Corporation - Inventors: Robert Steven Newberry - Web page: https://patentgrep.com/patent/US20170281065A1 ## CPC - A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes} - A61B 5/0004: {characterised by the type of physiological signal transmitted} - A61B 5/0022: {Monitoring a patient using a global network, e.g. telephone networks, internet} - A61B 5/1455: using optical sensors, e.g. spectral photometrical oximeters - A61B 5/6817: {Ear canal} - A61B 5/7235: {Details of waveform analysis (detecting specific parameters of the electrocardiograph cycle A61B5/349)} - A61B 5/743: {Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots} - G16H 40/67: for remote operation - A61B 5/681: {Wristwatch-type devices} - A61B 5/6826: {Finger} - A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors - A61B 2560/0228: using calibration standards - Y02A 90/10: Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE ## Abstract A biosensor includes a PPG circuit that emits light directed at living tissue at a plurality of wavelengths. A first and second spectral response of light reflected from the tissue is obtained around a first wavelength and a second wavelength. Using absorption coefficients for substances at the plurality of wavelengths, concentration levels of a plurality of substances such as Nitric Oxide may then be determined from the spectral responses. ## Claims ### Claim 1 A biosensor for monitoring nitric oxide (NO) of a patient in vivo, comprising: a PPG circuit configured to: generate at least a first spectral response for light reflected around a first wavelength from skin tissue of the patient; generate at least a second spectral response for light reflected around a second wavelength from the skin tissue of the patient; a processing circuit configured to: obtain a value Lλ1 using the first spectral response, wherein the value Lλ1 isolates the first spectral response due to pulsating arterial blood flow; obtain a value Lλ2 using the second spectral response, wherein the value Lλ2 isolates the second spectral response due to pulsating arterial blood flow; obtain a value Rλ1, λ2 from a ratio of the value Lλ1 and the value Lλ2; and obtain a concentration level of nitric oxide using the value Rλ1, λ2 and a calibration database, wherein the calibration database is used to correlate the value Rλ1, λ2 and the concentration level of nitric oxide (NO). ### Claim 2 (depends on 1) The biosensor of claim 1, further comprising at least one of: a wireless transceiver configured to transmit the concentration level of nitric oxide to another device; or a port for a wired connection to communicate the concentration level of nitric oxide to another device. ### Claim 3 (depends on 1) The biosensor of claim 1, wherein the first wavelength has a high absorption coefficient for nitric oxide in arterial blood flow and is in a range of approximately 370 nm to 410 nm. ### Claim 4 (depends on 3) The biosensor of claim 3, wherein the second wavelength has a lower absorption coefficient for nitric oxide in arterial blood flow. ### Claim 5 (depends on 1) The biosensor of claim 1, wherein the calibration database includes a range of Rλ1, λ2 values and correlated concentration levels of nitric oxide and wherein the calibration database is generated using nitric oxide level measurements obtained from a large sample population. ### Claim 6 (depends on 5) The biosensor of claim 5, wherein the calibration database includes different correlations between the R values and NO concentration levels depending on the underlying skin tissue. ### Claim 7 (depends on 1) The biosensor of claim 1, further configured to: obtain a concentration level of one or more hemoglobin species; and compensate for the concentration level of the one or more hemoglobin species to determine the value Rλ1, λ2. ### Claim 8 (depends on 7) The biosensor of claim 7, wherein the concentration level of the one or more hemoglobin species is determined by: analyzing spectral response of a plurality of wavelengths to determine differential absorption signals for each hemoglobin species; and using a Beer-Lambert matrix equation for determining the concentration levels of the one or more hemoglobin species. ### Claim 9 A biosensor for monitoring nitric oxide (NO) of a patient in vivo, comprising: a PPG circuit configured to: generate at least one spectral response from light reflected around a range of wavelengths from skin tissue of the patient; a processing circuit configured to: determine an absorbance spectra curve for hemoglobin from the spectral response; determine a degree of shift of the absorbance spectra curve of hemoglobin due at least to a presence of NO; access a calibration database that include correlations of degrees of shifts of the absorbance spectra to concentration levels of nitric oxide (NO); and obtain a concentration level of nitric oxide using the calibration database. ### Claim 10 (depends on 9) The biosensor of claim 9, wherein the processing circuit is configured to determine a degree of shift of the absorbance spectra curve of hemoglobin by: comparing a peak of the absorbance spectra curve of hemoglobin to an absorption peak of a known absorbance spectra curve of hemoglobin in an absence of NO. ### Claim 11 (depends on 10) The biosensor of claim 10, wherein the hemoglobin includes deoxygenated hemoglobin and the absorption peak is around 430 nm in an absence of NO. ### Claim 12 (depends on 11) The biosensor of claim 11, wherein the processing circuit is configured to determine a degree of shift of the absorbance spectra curve of deoxygenated hemoglobin by: determining a degree of shift of the peak of the absorbance spectra curve of deoxygenated hemoglobin from around 430 nm. ### Claim 13 (depends on 10) The biosensor of claim 10, wherein the hemoglobin includes oxygenated hemoglobin and the absorption peak is around 421 nm in an absence of NO. ### Claim 14 (depends on 13) The biosensor of claim 13, wherein the processing circuit is configured to determine a degree of shift of the absorbance spectra curve of oxygenated hemoglobin by: determining a degree of shift of the peak of the absorbance spectra curve of oxygenated hemoglobin from around 421 nm. ### Claim 15 A method for monitoring nitric oxide (NO) of a patient in vivo, comprising: obtaining at least a first spectral response for light reflected around a first wavelength from skin tissue of the patient; obtaining at least a second spectral response for light reflected around a second wavelength from the skin tissue of the patient; obtaining a value Lλ1 using the first spectral response, wherein the value Lλ1 isolates the first spectral response due to pulsating arterial blood flow; obtaining a value Lλ2 using the second spectral response, wherein the value Lλ2 isolates the second spectral response due to pulsating arterial blood flow; obtaining a value Rλ1, λ2 from a ratio of the value Lλ1 and the value Lλ2; and obtaining a concentration level of nitric oxide using the value Rλ1, λ2 and a calibration database, wherein the calibration database correlates the value Rλ1, λ2 and the concentration level of nitric oxide (NO). ### Claim 16 (depends on 15) The method of claim 15, wherein the first wavelength has a high absorption coefficient for nitric oxide in arterial blood flow and is in a range of approximately 370 nm to 410 nm. ### Claim 17 (depends on 16) The method of claim 16, wherein the second wavelength has a lower absorption coefficient for nitric oxide in arterial blood flow. ### Claim 18 (depends on 15) The method of claim 15, wherein the calibration database includes a range of Rλ1, λ2 values and correlated concentration levels of nitric oxide and wherein the calibration database is generated using nitric oxide level measurements obtained from a large sample population. ### Claim 19 (depends on 18) The method of claim 18, wherein the calibration database includes different correlations between the R values and NO concentration levels depending on the underlying skin tissue. ### Claim 20 (depends on 15) The method of claim 15, further comprising: obtaining a concentration level of one or more hemoglobin species; and compensating for the concentration level of the one or more hemoglobin species to determine the value Rλ1, λ2.