Smart sweat stimulation and sensing devices
Inventors
Heikenfeld, Jason • Begtrup, Gavi • Bertrand, Jacob
Assignees
Publication Number
US-10646142-B2
Publication Date
2020-05-12
Expiration Date
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Abstract
The disclosed invention provides sweat sensing devices with smart sweat stimulation and sensing embodiments: which improve the dependability and predictability of sweat sampling rates; achieve a desired number of sweat sampling events per day while minimizing skin irritation and prolonging device lifespan; and use physical, optical or thermal sweat stimulation to augment or replace chemical sweat stimulation.
Core Innovation
The disclosed invention provides a sweat sensor device capable of smart sweat stimulation and sensing, which improves the dependability and predictability of sweat sampling rates and achieves a desired number of sweat sampling events per day while minimizing skin irritation and prolonging device lifespan. The disclosed devices and methods use physical, optical, or thermal sweat stimulation to augment or replace chemical sweat stimulation and bring sweat stimulating, sweat collecting, and/or sweat sensing technology into intimate proximity with sweat as it is generated.
The background identifies that sweat sensing has been limited by a slow and inconvenient process of sweat stimulation, sample collection, transport, and laboratory analysis that has constrained continuous or repeated biosensing and favored blood draws for many applications. Sweat is described as having the least predictable sampling rate among common physiological fluids, which limits the ability to obtain chronologically assured samples without technological measures to control sampling rate and timing.
The disclosure describes devices and methods that control or measure sweat generation rate and sweat chronological assurance using combinations of sensors, stimulation components, materials, electronics, microfluidics, and algorithms. The devices may measure sweat rate by means such as skin impedance, galvanic skin response, or sweat ion concentrations, determine a sweat onset temperature, and apply thermal, optical, chemical, or other stimulation or thermally insulating structures to increase sampling efficiency, reduce irritation, and improve sampling predictability.
Claims Coverage
Overview: The independent claim includes six main inventive features related to placement, scheduling, measurement, determination, conditional stimulation, and analyte measurement.
Applying a sweat sensing device to a wearer's skin
Applying a sweat sensing device to a wearer's skin.
Scheduling required sweat sampling events
Scheduling a plurality of sweat sampling events that are required for an application.
Measuring sweat generation rate
Measuring a sweat generation rate from the wearer's skin.
Determining a sweat onset temperature
Determining a sweat onset temperature.
Stimulating sweat when generation rate is insufficient to ensure chronological assurance
Stimulating sweat if the sweat generation rate is insufficient to provide each of the plurality of sweat sampling events with a sweat sample having a chronological assurance.
Taking multiple sweat analyte readings
Taking a plurality of sweat analyte readings.
The independent claim defines a method that combines placement of a sweat sensing device, scheduling of multiple sampling events, measurement of sweat generation rate, determination of sweat onset temperature, conditional stimulation to ensure chronologically assured samples, and taking multiple sweat analyte readings.
Stated Advantages
Improve the dependability and predictability of sweat sampling rates.
Achieve a desired number of sweat sampling events per day while minimizing skin irritation and prolonging device lifespan.
Use physical, optical, or thermal sweat stimulation to augment or replace chemical sweat stimulation.
More efficient stimulation reduces device resource use and skin irritation and can prolong device life; thermal stimulation can increase capillary blood flow and biomarker partitioning into sweat, potentially allowing shorter sampling intervals or improved solute correlation between sweat and blood.
Documented Applications
Athletics
Neonatology
Pharmacological monitoring
Personal digital health
Infant chloride assays for Cystic Fibrosis
Illicit drug monitoring patches
Continuous or repeated biosensing
Measurement of cortisol in sweat (example use case)
Detection of illicit substances as exemplified by the PharmCheck patch
Applications involving biomarkers whose sweat concentrations vary with sweat rate, such as cytokines (discussed as an example of analyte-rate dependence)
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