Analyte detection from breath samples
Inventors
Lynn, Michael Scott • Heanue, Joseph A. • Anekal, Samartha G. • LIMTAO, Kevin M. • Dunk, Kevin Bradford • Schuster, Jeffrey A.
Assignees
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Publication Number
US-11747353-B1
Publication Date
2023-09-05
Expiration Date
Abstract
Systems and techniques for collecting and analyzing breath samples to detect one or more target analytes are disclosed.
Core Innovation
The invention evaluates a tetrahydrocannabinol (THC) level in a breath sample by drawing a portion of the breath sample into a reaction channel of a microfluidic test cartridge. The test cartridge includes a microfluidic device with one or more reaction channel walls having a THC antibody surface-bound, and THC from the drawn breath portion is captured by binding to the THC antibody on the reaction channel walls.
The captured THC amount is determined by flowing a diazotized fluorophore into the reaction channel to form a solution in which the diazotized fluorophore binds to the captured THC, forming a diazotized fluorophore-THC adduct. The diazotized fluorophore-THC adduct is exposed to a light source to produce fluorescence, and an intensity of the fluorescence is measured and used to determine the amount of THC captured from the breath sample.
The determined amount of THC is compared to a threshold level for THC in breath. The threshold level is based on a measured intensity of fluorescence from similar measurements performed for a control amount of THC, and the method indicates whether the determined THC amount exceeds the threshold level using a visible and/or audible signal and/or readout on a display associated with a device performing the determining and comparing.
Claims Coverage
Independent claim clm-00001 covers a microfluidic cartridge immunoassay method with diazotized fluorophore fluorescence detection, threshold comparison, and visible/audible/display indication. The family further includes refinements in dependent claims, including threshold derivation based on a baseline maximum associated with an impairment window concept, optional washing prior to fluorescence, and alternative assay formats and multi-analyte measurement for ethanol.
Microfluidic breath sampling with surface-bound THC antibody capture
A method drawing a portion of a breath sample into a reaction channel of a test cartridge, where the test cartridge is a microfluidic device with reaction channel walls having a THC antibody surface-bound, and THC from the breath portion is captured by binding to the THC antibody.
Diazotized fluorophore-THC adduct fluorescence determination
A determination of captured THC amount by flowing a diazotized fluorophore into the reaction channel to form a diazotized fluorophore-THC adduct, exposing the adduct to a light source to produce fluorescence, measuring fluorescence intensity, and determining the amount of THC captured based on the measured intensity.
Fluorescence-based threshold comparison and indication
Comparing the determined amount of THC captured to a threshold level for THC in breath, where the threshold level is based on a measured intensity of fluorescence from similar measurements for a control amount of THC, and indicating whether the determined amount exceeds the threshold using a visible and/or audible signal and/or a readout on a display associated with the device used for determining and comparing.
Threshold level based on baseline maximum and impairment window concept
The threshold level is correlated with a baseline maximum level of THC in breath associated with consumption of THC outside a window of THC-associated impairment.
Washing prior to fluorescence exposure
Prior to exposing the diazotized fluorophore-THC adduct to a light source, washing away unbound breath constituents and diazotized fluorophore from the reaction channel.
LOCI donor/acceptor bead competitive binding format with synthetic THC
Capture THC and determine the THC amount using a luminescent oxygen channeling immunoassay (LOCI) with donor beads and acceptor beads, involving competitive binding including synthetic THC.
Chemiluminescent competitive format with enzyme-conjugated synthetic THC antigen
Assay THC using a surface-bound THC antibody and competitive binding against a known amount of an enzyme-conjugated synthetic THC antigen, followed by flowing a chemiluminescent substrate to the enzyme-activated substrate and measuring chemiluminescence to determine the captured THC amount.
Multi-analyte measurement of ethanol and THC from the same breath sample
The second substance is ethanol, and both THC and ethanol are measured from the same breath sample.
Overall claim coverage centers on evaluating THC in breath using a microfluidic cartridge with a surface-bound THC antibody, forming a diazotized fluorophore-THC adduct for fluorescence intensity measurement, then comparing to a fluorescence-based threshold and indicating exceedance via visible/audible/display signals. Dependent refinements include deriving the threshold using a baseline maximum and an impairment window concept, optionally washing before fluorescence, and alternative detection formats including LOCI with donor/acceptor beads and competitive chemiluminescent enzyme-based assays, plus optional multi-analyte measurement for ethanol from the same breath sample.
Stated Advantages
Determines and evaluates whether a determined THC amount exceeds a fluorescence-based threshold for THC in breath using a visible and/or audible signal and/or a display readout.
Documented Applications
Evaluating tetrahydrocannabinol (THC) level in a breath sample for making an exceedance determination relative to a threshold level for THC in breath.
Measuring ethanol and THC from the same breath sample.
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