[go: up one dir, main page]

WO2025221460A1 - Tatouage électronique mobile et conforme pour la surveillance ambulatoire de l'hydratation de l'ensemble du corps - Google Patents

Tatouage électronique mobile et conforme pour la surveillance ambulatoire de l'hydratation de l'ensemble du corps

Info

Publication number
WO2025221460A1
WO2025221460A1 PCT/US2025/022793 US2025022793W WO2025221460A1 WO 2025221460 A1 WO2025221460 A1 WO 2025221460A1 US 2025022793 W US2025022793 W US 2025022793W WO 2025221460 A1 WO2025221460 A1 WO 2025221460A1
Authority
WO
WIPO (PCT)
Prior art keywords
stacked
conformable
design
flexible
mobile sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/US2025/022793
Other languages
English (en)
Inventor
Nanshu LU
Matija JANKOVIC
Sarnab BHATTACHARYA
Seungmin Kang
Edward COYLE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Texas System
University of Texas at Austin
Original Assignee
University of Texas System
University of Texas at Austin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Texas System, University of Texas at Austin filed Critical University of Texas System
Publication of WO2025221460A1 publication Critical patent/WO2025221460A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/25—Bioelectric electrodes therefor
    • A61B5/279—Bioelectric electrodes therefor specially adapted for particular uses
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
    • A61B5/0015—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network characterised by features of the telemetry system
    • A61B5/0022—Monitoring a patient using a global network, e.g. telephone networks, internet
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
    • A61B5/053—Measuring electrical impedance or conductance of a portion of the body
    • A61B5/0537—Measuring body composition by impedance, e.g. tissue hydration or fat content
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/25—Bioelectric electrodes therefor
    • A61B5/251—Means for maintaining electrode contact with the body
    • A61B5/257—Means for maintaining electrode contact with the body using adhesive means, e.g. adhesive pads or tapes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
    • A61B5/30—Input circuits therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
    • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
    • A61B5/443—Evaluating skin constituents, e.g. elastin, melanin, water
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/48—Other medical applications
    • A61B5/4869—Determining body composition
    • A61B5/4875—Hydration status, fluid retention of the body
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6824—Arm or wrist
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/683—Means for maintaining contact with the body
    • A61B5/6832—Means for maintaining contact with the body using adhesives
    • A61B5/6833—Adhesive patches
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/04—Constructional details of apparatus
    • A61B2560/0406—Constructional details of apparatus specially shaped apparatus housings
    • A61B2560/0412—Low-profile patch shaped housings
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/16—Details of sensor housings or probes; Details of structural supports for sensors
    • A61B2562/164—Details of sensor housings or probes; Details of structural supports for sensors the sensor is mounted in or on a conformable substrate or carrier
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/16—Details of sensor housings or probes; Details of structural supports for sensors
    • A61B2562/166—Details of sensor housings or probes; Details of structural supports for sensors the sensor is mounted on a specially adapted printed circuit board

Definitions

  • Dehydration is a common condition that affects individuals of all ages. It is known to cause complications when left untreated for an extended amount of time, and when other medical conditions are present, and can cause hospitalization and even death in certain circumstances. Dehydration has been reported to occur in 17-28% of adults in the United States. Based on this statistic alone, of the 260 million adults in the US (aged 18 or over), it is estimated that between 44 and 73 million individuals are dehydrated, to some extent, at any given time. However, many of the mild and severe symptoms can be prevented if a robust, accurate, and wearable whole -body hydration monitor were to be developed. It is worth noting that there are certain groups of individuals that would derive great benefit from such a device including but not limited to the elderly, athletes, people exposed to extreme environments, first responders, hospital patients, etc.
  • the elderly The number of elderly individuals (age 65 or over) reached a staggering 55.8 million (16.8% of the population) in the United States in 2020.
  • the elderly naturally have a lower volume of water in their bodies, have a higher risk of already suffering from various health conditions, and are more likely to be taking various medications (which may have a diuretic effect). These factors mean that such individuals are more vulnerable to becoming dehydrated.
  • Extreme environment individuals Individuals who work in extreme environments (e.g., armed-forces personnel, construction workers, etc.) are also more susceptible to dehydration. For example, these individuals often find themselves in harsh environments, where extreme heat and humidity are present, and may suffer from physical and mental impairment (i.e., fatigue) due to dehydration. For example, in 2022, the United States had 1.4 million active military personnel. Moreover, as of 2023, there are approximately 10 million individuals in the United States that are employed in the construction industry. These individuals would derive great benefit from a wholebody hydration monitor to ensure they are staying well-hydrated in these extreme environments, as well as training scenarios.
  • First responders Similar to the grouping above, first responders (particularly firefighters) are often in extreme environments in which they are more susceptible to dehydration. As of 2022, there are an estimated 4.6 million individuals that serve as career and/or volunteer firefighters, police, emergency medical technicians, and paramedics in the United States.
  • a device, system and method of a thin, light, flexible, and skin-conformal form factor e-tattoo that laminates onto the body e.g., the upper arm region
  • the body e.g., the upper arm region
  • the disclosed device monitors whole-body hydration in an ambulatory setting.
  • the device comprises a plurality (e.g., four) of probes that provide four-terminal (i.e., kelvin) bioimpedance sensing and enabling non-invasive continuous monitoring of whole-body hydration.
  • the wireless streaming capabilities enable data offloading for real-time data analysis and condition detection, as well as long term storage.
  • the e-tattoo has an effective thickness (without battery) of 1.3mm. All sensing, computation and wireless systems are integrated into the wearable e-tattoo.
  • the device leverages four-probe bioimpedance sensing in order to measure the segmental cross-arm bioimpedance in a non-invasive, wearable, and continuous manner.
  • Biocompatible graphite based dry electrodes allow monitoring for days without degradation in signal quality or any skin irritation.
  • FIG. 1A illustrates an on-body application of an exemplary wearable bioimpedance-based e-tattoo for whole-body hydration assessment.
  • FIG. IB illustrates four-terminal cross-arm bioimpedance sensing of an exemplary wearable bioimpedance-based e-tattoo.
  • FIG. 1C is an illustration of the flow of current in human cells at low and high frequencies.
  • FIG. ID illustrates an exemplary bioimpedance vector analysis (BIVA) plot with various identified body-composition and hydration states.
  • BIVA bioimpedance vector analysis
  • FIG. IE is an illustration of an exemplary system for measuring and/or monitoring whole-body hydration using the disclosed e-tattoo.
  • FIG. 2A illustrates a finite element model of the brachium and its electrical simulations using a three-dimensional brachium model, with four different tissue layers (i.e., skin, fat, muscle, bone) and electrodes with complex electrical characteristics defined for each material type.
  • FIG. 2B illustrates electric field plots across two slices (XY and YZ axes) of the finite-element model of the brachium.
  • FIG. 2C illustrates simulated resistance, reactance, and impedance as a function of electrode spacing parameter, d.
  • FIG. 2D illustrates experimental data for resistance, reactance, and impedance as a function of electrode spacing parameter, d.
  • FIG. 2E illustrates impedance as a function of muscle resistivity for varying electrode spacings.
  • FIG. 2F illustrates the change in impedance as a function of muscle resistivity for varying electrode spacings.
  • FIG. 2G illustrates impedance as a function of muscle resistivity for cross-arm and single- side electrode configurations.
  • FIG. 2H illustrates the change in impedance as a function of muscle resistivity for cross-arm and single-side electrode configurations.
  • FIG. 3A illustrates an exemplary block diagram of the hardware components of an embodiment of the disclosed bioimpedance e-tattoo.
  • FIG. 3B illustrates an exploded 3D view of the flexible printed circuit (FPC) layer and electronic components of an exemplary bioimpedance e-tattoo.
  • FPC flexible printed circuit
  • FIG. 3C illustrates active power draw of an exemplary bioimpedance e-tattoo during operation.
  • Average current in this example is 0.879 mA.
  • FIG. 3D illustrates contact impedance as a function of frequency for graphite polyurethane (GPU) film and wet-gel red dot (Red Dot Electrodes, 3M) electrodes for electrophysiological sensing.
  • GPU graphite polyurethane
  • 3M wet-gel red dot
  • FIG. 3E illustrates an exemplary resistance- strain curve for an embodiment of a bioimpedance e-tattoo.
  • FIG. 3F illustrates arm Bio-Z data collected for 45 minutes, during which a single participant engaged in muscle contraction exercises.
  • FIG. 3G are images of an exemplary EcoflexTM encased bioimpedance e-tattoo and characterizing features, namely (I) size of the FPC layer relative to a single USA quarter, (II) flexibility, and (III) inherent stretchability of serpentine interconnects.
  • FIG. 4A illustrates diuretic-induced dehydration experimental protocol for wholebody hydration assessment.
  • Blue [-60, 0] represents no data collection
  • orange [0, 30] represents data omitted due to electrode settling effects
  • green [30, 180] represents useful data.
  • FIG. 4B illustrates per-participant normalized arm impedance versus time following the protocol presented in FIG. 4A.
  • FIG. 4C illustrates per-participant arm-diameter-normalized arm impedance versus percent body weight loss.
  • FIG. 4D illustrates a BIVA plot for arm impedance data.
  • FIG. 4E illustrates per-participant height-normalized body impedance versus percent body weight loss.
  • FIG. 4F illustrates a BIVA plot for whole-body impedance data.
  • FIGS. 4G - 4N each illustrates a BIVA plot for an individual participant corresponding to discrete measurements shown in FIG. 4A for arm impedance and whole-body impedance data.
  • FIG. 40 illustrates the relationship between BIVA vector length and percent body weight loss for all participants for arm impedance (left) and whole-body impedance (right) data.
  • FIG. 5A illustrates arm bioimpedance versus time.
  • FIG. 5B illustrates arm impedance versus percent body weight loss during the diuretic dehydration period denoted in FIG. 5 A.
  • FIG. 5C illustrates a BIVA plot for arm impedance data with data points corresponding to the dashed lines illustrated in FIG. 5A.
  • FIG. 5D illustrates an exemplary e-tattoo hydration sensor under various muscle contractions showcasing its ability to monitor in an ambulatory environment.
  • FIGS. 51 - 5L illustrate the diuretic-protocol results conducted using a single- side electrode configuration set up on two participants, where FIG. 51 illustrates the single-side electrode configuration setup using a hydration e-tattoo; FIG. 5J illustrates post-processed arm resistance, reactance, and impedance data for the two participants undergoing diureticdehydration protocol; FIG. 5K illustrates a linear relationship between per-participant arm- diameter-normalized arm impedance and percent body weight loss; and FIG. 5L illustrates a BIVA plot for arm impedance data for the two participants.
  • FIGS. 5M - 5P illustrate diuretic -protocol results conducted using a rigid wrist- worn cross-arm configuration setup on a single human participant, where FIG. 5M illustrates the crossarm configuration setup;
  • FIG. 5N illustrates post-processed wrist resistance, reactance, and impedance data undergoing diuretic-dehydration protocol, where large spikes in data can be due to sudden wrist movements;
  • FIG. 50 illustrates a linear relationship between wrist impedance and percent body weight loss;
  • FIG. 5P illustrates a serial BIVA plot for wrist impedance data, sselling displacement in line with a minor ellipse axis due to minimal reactance variations.
  • FIG. 5Q illustrates a schematic representation of a sensing paradigm of the exemplary system.
  • FIGS. 6 A - 6C illustrate conventional methods for dehydration assessment.
  • a wearable, stretchable, thin, and lightweight, body e.g., arm
  • laminated electronic tattoo e.g., e-tattoo
  • the e-tattoo uses a plurality of probes for four-terminal (i.e., kelvin) bioimpedance sensing to monitor whole-body hydration.
  • the e-tattoo attaches to the upper arm (i.e., brachium) region of the body to capture the segmental cross-arm bioimpedance and evaluate whole-body hydration status.
  • Bioimpedance sensing is a non-invasive sensing paradigm which relies on injecting a small amplitude, high frequency current into the body and sensing the voltage response due to this stimulation.
  • bioimpedance relates to the effective resistance of biological tissue to alternating current.
  • bioimpedance vector analysis BIVA
  • the disclosed e-tattoo utilizes biocompatible electrodes (e.g., graphite polyurethane-based), cut into serpentine- structured patterns for stretchability and higher conformability, that interface with human skin to capture electrophysiological data.
  • the device is completely mobile and capable of wireless streaming (e.g., over Bluetooth) data in real time to one or more host devices.
  • the combined hardware and software features of the e-tattoo provide ultra-low power consumption and prolonged battery life. By measuring the segmental arm bioimpedance, the e-tattoo captures dehydration and rehydration periods. Dehydration has been shown to increase the burden on the body’s cardiovascular system and increase core body temperatures.
  • the capabilities of this e- tattoo enable continuous tracking of hydration status, which has significant implications for various individuals, especially those who are more prone to becoming dehydrated. For example, the elderly, who naturally have a lower volume of water in their bodies and have a higher risk of already suffering from various health conditions, are more susceptible to dehydration. Armed- forces personnel and construction workers often work in extreme environments (e.g., high heat and humidity conditions) where dehydration is more common.
  • body hydration status is a major concern for high-performance athletes, who seek to optimize their fluid intake in order to maximize performance, prevent injury, and aid recovery.
  • Continuous monitoring and the wearable and completely mobile form factor of the disclosed device provides better time resolution, and therefore better sensitivity to fluid loss, as well as long-term operation for capturing the human body fluid status variation in a daily living environment (i.e., >24 hours).
  • Some instances of the disclosed e-tattoo comprise a polyimide substrate with copper traces comprising the on-board electronics and the electrodes are made from biocompatible materials such as dry carbon-based graphite film.
  • the e-tattoo is a multilayered device, with only the electrodes being in contact with the skin, and the electronics being completely isolated from the human body by being encased.
  • An electrical connection is made between the layers (e.g., electrodes and electronics) via a conductive layer such as anisotropic conductive film (ACF). This ensures that the electrodes are detachable and can be disposed of, and the electronics can be reused with a new electrode layer.
  • ACF anisotropic conductive film
  • the disclosed e-tattoo has an extremely low power consumption (approximately 1.6 mW) compared to other contemporary wearable devices.
  • Testing of exemplary embodiments of the disclosed e-tattoo to measure arm impedance continuously and correlating this to body weight loss, which is considered a gold standard when capturing dehydration periods of less than 12 hours, yielded high correlation (R 0.95) among eight human subjects during a diuretic-induced dehydration study.
  • the disclosed e-tattoo can be attached to other parts of the body (for example, other limbs of the body (e.g., leg)) that possess enough muscle mass to reflect body hydration.
  • the e-tattoo device can be attached to other parts of the body to sense other physiological parameters in addition to hydration such as electrocardiogram, respiration, human activity detection, etc. These other attachment locations and additional uses of the e-tattoo are considered within the scope of this disclosure.
  • a wearable bioimpedance-based electronic tattoo (e-tattoo) is disclosed that continuously and non-invasively monitors whole-body hydration (WBH).
  • WBH whole-body hydration
  • the disclosed e-tattoo is affixed to the upper arm (brachium) using two pairs of temporary tattoo electrodes to capture segmental cross-arm bioimpedance in a kelvin sensing configuration as shown in Fig. IB.
  • a high frequency alternating current is utilized that passes through both extracellular (ECF) and intracellular (ICF) fluids (see Fig.lC).
  • Bioimpedance vector analysis (BIVA), and/or various other analyses, is then employed to evaluate whole -body hydration change, as shown in Fig. ID.
  • Bioimpedance for hydration sensing typically employs frequencies in the 5-500 kHz range. In one instance, the disclosed device, and the analysis provided, employs a 40 kHz alternating current, although this frequency can be programmed to other values.
  • BIVA which is typically utilized in whole-body impedance studies, employs a frequency of 50 kHz (although any other frequency value can be realized).
  • the e-tattoo is characterized by its flexible sensor design, which enables it to conform to the natural curvature of the skin, ensuring seamless operation and minimizing any inconvenience to the wearer.
  • the raw bioimpedance signal (Bio-Z) is wirelessly transmitted in real-time via wireless protocols such as Bluetooth Low Energy (BLE), ZigBee, etc. to a host device 102.
  • wireless protocols such as Bluetooth Low Energy (BLE), ZigBee, etc.
  • BLE Bluetooth Low Energy
  • ZigBee ZigBee
  • the disclosed hydration e-tattoo demonstrates monitoring of WBH in various conditions, highlighting the ability and feasibility of wearable hydration monitoring in everyday life.
  • the disclosed e-tattoo is used to monitor bioimpedance. Relative changes in bioimpedance (from some starting point) over time are correlated to percent body weight loss over time. It has been found that upper arm bioimpedance can serve as a reliable, continuous proxy of whole-body hydration that is cost-effective and highly accessible.
  • BIVA is employed to highlight that the disclosed device and the resistance/reactance changes that occur during dehydration, are consistent with trends associated with the loss of body water and previous literature utilizing whole-body impedance (an established method).
  • the disclosed device may be used to attain an approximation of whole-body hydration status using different methods. For example, this may be achieved by:
  • Day 1 Perform a calibration period of the device by wearing the device for one day and periodically logging body weight, while tracking arm bioimpedance with the e-tattoo.
  • Bioimpedance sensing necessitates strategic placement of distinct pairs of electrodes for both injection and sensing purposes. These electrodes serve the function of stimulating the tissue through the application of a high-frequency AC signal and concurrently measuring the resultant potential difference, which fluctuates in response to impedance variations within the underlying tissue.
  • these sensors When deployed around the brachium, these sensors exhibit sensitivity to various factors such as shifts in body fluids (e.g., blood flow, tissue hydration) and motion.
  • body fluids e.g., blood flow, tissue hydration
  • simulations were conducted to ascertain: 1) the optimal sensing configuration, and 2) the most favorable current-to-voltage electrode spacing. The results of these simulations guided the design of the device described herein.
  • Previous applications of bioimpedance sensing typically adopt an electrode arrangement where all electrodes are positioned linearly along various arteries of the body (e.g., wrist, ankle, neck), with the outer electrodes serving for current injection. This configuration is typically used so that temporal features (e.g., pulse transit time) can be captured. However, the disclosed embodiments have no such requirements.
  • a four-layer Finite Element Model (FEM) of the brachium was developed (Fig. 2A).
  • FEM Finite Element Model
  • Fig. 2A To characterize the electrical properties of each tissue type, frequency-dependent parameters derived from Cole-Cole equations were employed. The entire geometry illustrated in Fig. 2A was subjected to simulation under various configurations by manipulating the electrode spacing through a parametric sweep of the parameter d. For these simulations, 100 pA of current, at an operating frequency of 40 kHz, was employed [40]. Voltage responses were captured via two voltage domain probes. A total of four electrodes (i.e., one pair for injection and one pair for sensing) are used to initiate four-terminal (Kelvin) Bio-Z sensing.
  • the conductivity and relative permittivity of skin were chosen as 0.00025 S/m and 1128.3, respectively.
  • the conductivity and relative permittivity of fat were chosen as 0.024 S/m and 215.2, respectively.
  • the conductivity and relative permittivity of muscle were chosen as 0.350 S/m and 10988, respectively.
  • the conductivity and relative permittivity of bone were chosen as 0.021 S/m and 281.1, respectively.
  • Voltage domain probes were assigned to the sensing electrodes to capture the voltage potential as a function of electrode spacing and configuration.
  • Table 1 shows the tissue and geometric properties used in the COMSOL simulation for the four-layer FEM model of the brachium shown in Fig. 2A.
  • Fig. 2B depicts electric field density plots across two slices of the model.
  • the cross-arm configuration showcases current passing through the entire geometry of the arm. With voltage sensing electrodes close by, the response due to stimulation of the entire arm would be captured. In contrast, however, a linear arrangement appears to have current pass through only half the geometry, which influences the captured response and, as a result, does not provide a complete picture of arm impedance changes when undergoing dehydration.
  • the distance (d) between the voltage sensing electrodes and the current injection electrodes plays a role in capturing the response due to stimulation.
  • the current density is highest directly over the injection sites and reduces abruptly as you move away (see Fig. 2B).
  • the captured response is therefore likely to significantly reduce as the voltage sensing electrodes are displaced away from the injection site.
  • Fig. 2C highlights this behavior by illustrating the simulated resistance, reactance, and impedance as functions of the d parameter. Namely, simulated responses are at their maximum at smaller values of d and decline as the d parameter increases. This behavior is attributable to the inability of the voltage sensing electrodes to capture a substantial portion of the response generated by current stimulation when the voltage sensing electrodes are positioned at a considerable distance from the injection electrodes.
  • embodiments of the e-tattoo device comprise a flexible arm-laminated e-tattoo, capable of measuring bioimpedance in a completely mobile manner.
  • a flexible arm-laminated e-tattoo is generally comprised of an electrode layer, a flexible printed circuit (FPC) layer, and typically, a cover layer.
  • FPC flexible printed circuit
  • the electrode layer comprises two or more current injection electrodes and one or more voltage sensing electrodes that are made from biocompatible materials such as graphite polyurethane film and laminated onto a first side of a first flexible, stretchable insulating substrate.
  • biocompatible materials such as graphite polyurethane film
  • Each electrode forms an electrode pattern on the first side of the first flexible, stretchable insulating substrate and each electrode is configured to flex and stretch with the first flexible, stretchable insulating substrate to conform to the epidermis of a wearer.
  • the electrode pattern on the first side of the first flexible, stretchable insulating substrate is serpentine shaped, and each electrode pattern generally includes one or more terminal pads for connection to an interconnect.
  • the first flexible, stretchable insulating substrate may be comprised of transparent or substantially transparent materials.
  • the first flexible, stretchable insulating substrate comprises a polyurethane film medical dressing, such as TegadermTM (3M, Saint Paul, MN), having an adhesive layer on the first side of the first flexible, stretchable insulating substrate. Electrical contact is made with the electrodes from a second side of the first flexible, stretchable insulating substrate through holes defined by the first flexible, stretchable insulating substrate and a conductive material such as an anisotropic conductive film (ACF) acts as an adhesive and conductor between electrodes and electronics.
  • a polyurethane film medical dressing such as TegadermTM (3M, Saint Paul, MN)
  • ACF anisotropic conductive film
  • the flexible printed circuit (FPC) layer having a first side and a second side.
  • the second side of the FPC layer may be covered with a third flexible substrate that covers the first flexible, stretchable insulating substrate and the FPC layer.
  • this third layer of material may comprise TegadermTM.
  • a portion of the third flexible substrate may be removed to define one or more holes that expose a power source (e.g., a battery) mounted on the second side of the FPC layer. In this way, the power source can be replaced as needed without having to replace the entire device.
  • the FPC layer may be comprised of transparent or substantially transparent materials.
  • the FPC layer comprises electronics disposed at least partially on the second side of the FPC layer.
  • the FPC layer comprises or at least partially comprises polyimide.
  • the first side of the second flexible insulating substrate is in substantial contact with the second side of the first flexible, stretchable insulating substrate.
  • the electronics comprise a processor such as a nRF52832 (Nordic Semiconductor, USA) central processing unit (CPU).
  • CPU central processing unit
  • the electronics may be a communications interface such as a Bluetooth Low Energy (BLE) transceiver that may, or may not, be integrated into the CPU.
  • BLE Bluetooth Low Energy
  • BLE Bluetooth Low Energy
  • Integrated BLE functionality additionally facilitates real-time transmission of data from the device to a designated receiver and/or host
  • the designated receiver may comprise a smartphone such as an Android or IOS-based smartphone running a custom-designed application.
  • the smartphone may comprise one or more processors that are used to analyze or at least partially analyze the data.
  • the designated receiver may further transmit the data to a host comprising one or more processors for analysis. In some instances, that data may be transmitted directly to the host comprising one or more processors.
  • the AFE may comprise a MAX30002 AFE (Maxim Integrated), which serves as a single-channel Bio-Z sensor and is linked to the CPU via the serial peripheral interface (SPI).
  • Power is supplied to the e-tattoo from a battery such as, for example, a small form factor 3.7 V 40 mAh lithium polymer (LiPo) battery, with all circuit elements being powered via a 1.8 V linear low-dropout (LDO) regulator (NCP161, onsemi).
  • LiPo lithium polymer
  • NCP161, onsemi linear low-dropout
  • the device features a FPC layer that has been patterned into islands and connected via serpentine tracks, illustrated in exploded and interfaced views in Fig. 3B.
  • the central island housing almost all passive components (e.g., resistors, capacitors, inductors) and integrated circuits (IC) responsible for sensing, processing, and communication, is strategically positioned to sit centrally on the head of the bicep, while interconnecting pads are situated on separate islands and interface with the electrode layer to initiate the cross-arm configuration on the brachium.
  • This island-based approach imparts stretchability, minimizes the number of interconnections, and provides a straightforward interface, all while maintaining optimal electronic density and promoting ease of operation.
  • Bio-Z sensing demands robust electrical contact with the skin, a requirement achieved through the utilization of graphite polyurethane film (GPU, Mineral Seal Corporation) laser cut into serpentine patterns and transferred onto commercial medical dressing (Tegaderm, 3M). Dry electrodes offer a number of advantages over conventional gel electrodes, such as immunity from signal degradation induced by electrode dehydration, an ultra-thin profile, and convenience for long-term wear.
  • anisotropic conductive film was employed in order to establish electrical connectivity between the FPC layer pads and GPU electrodes. Small holes were punctured onto the medical dressing to expose part of the electrodes where a piece of ACF was attached.
  • the embodiments of the disclosed e-tattoo prioritize user comfort, device re-usability, and long-term operation.
  • the disclosed e-tattoo employs an AC current of approximately 100 pA, or less, at 40 kHz for the purpose of injected stimulation.
  • a sampling frequency of approximately 0.2 Hz was chosen given that human hydration status is expected to undergo gradual rather than instantaneous variations. This choice of sampling frequency also serves to minimize power consumption.
  • Fig. 3C shows the active power draw of the e-tattoo during operation, with an average current draw of approximately 0.879 mA.
  • the skin-electrode interface i.e., “contact” impedance is a factor for sensors interfacing with human skin.
  • Fig. 3D illustrates the contact impedance for the GPU film electrodes and commercial wet gel electrodes. At the 40 kHz operating frequency, the contact impedance for the GPU film electrodes and wet gel electrodes measured approximately 4.1 kQ and 0.39 kQ, respectively. For an injection current of 100 pA, this impedance level remains well within the acceptable limits of the system.
  • Fig. 3E illustrates the FPC layer’s measured resistance under varying levels of strain.
  • the FPC layers demonstrates accurate measurement with minimal deviation, even when subjected to strains surpassing the established maximum threshold of 30% tolerated by human skin.
  • FIG. 3E showcase a serpentine interconnect before (left) and after (right) the strain experiment.
  • the right- most image depicts the serpentine at approximately 45% strain, displaying plastic deformation but measuring resistance with only 1.65% deviation.
  • Fig. 3F shows the arm Bio-Z data collected for 45 minutes, during which a single participant engaged in muscle contraction exercises. These exercises included medium and full bicep flexion interspersed with rest intervals. Medium muscle flexion periods involved the participant flexing their bicep muscle to maintain their arm at a 45-degree angle relative to a flat surface. Similarly, full muscle flexion was executed without constraining the arm angle, resulting in complete bicep flexion. Each flexion period lasted five minutes and consisted of alternating 15- second intervals of flexion and rest, repeated until the completion of the five-minute duration. This process was repeated twice.
  • the exemplary system is constructed using a double-layer FPC, where a polyimide (PI) substrate houses copper tracks on both the top and bottom layers.
  • the FPC comprises an island-serpentine configuration, incorporating two islands that house electronics and copper pads for electrode interfacing. These islands are connected to the main board via stretchable serpentine interconnects. Each serpentine interconnect comprises the copper tracks required to facilitate the connection between current injection and voltage sensing pad connections and the electronics.
  • the overall thickness of the FPC, inclusive of circuit elements measures approximately 200 pm.
  • the central region of the FPC which houses the majority of circuit components, is designed using rounded edges, like the shape of an eye.
  • This eye-shaped design in addition to the stretchable serpentine, provides better conformity to human skin and improved resistance against mechanical deformation.
  • the circuit elements were affixed to the FPC using lead (Pb) free soldering paste and the device was encapsulated in Ecoflex.
  • a diuretic-induced experimental protocol as outlined in Fig. 4A. Sessions commenced with the preparation of the participant’s upper arm skin, which served as the sensing site. This preparation procedure involved applying an exfoliating gel, wiping away any residue, wiping the area with a saline wipe, and drying it with a delicate task wipe. Subsequently, the device was affixed to the participants’ left arm. Attachment on the left arm was chosen given that all participants were rightarm dominant and to maintain uniformity across the participant cohort. During the data collection period, participants were permitted to engage in minor tasks, such as operating a phone or laptop device or reading a book, using their dominant (i.e., right) hand.
  • Furosemide is classified as a loop diuretic, which functions by inhibiting the reabsorption of sodium and chloride in the kidneys, thereby reducing water reabsorption and increasing urine production. Consequently, significant solute and water losses occur, resulting in dehydration with minimal change in (ECF) osmolality.
  • ECF ethylene glycol
  • This type of dehydration known as isotonic dehydration, is considered a suitable representation of the dehydration that occurs due to conditions such as diarrhea and vomiting.
  • the presented data trends in Fig. 4B are post-processed, involving the application of a median filter and mean filter to the raw data.
  • the median filter is employed to eliminate outliers or significant spikes caused by abrupt movements or motion.
  • a mean filter is applied to smooth the data and emphasize long-term trends for subsequent hydration assessment.
  • the normalization incorporated in Fig. 4B utilizes the initial arm impedance per participant. Namely,
  • a windowing scheme was implemented.
  • a 5-minute average window was applied on the Bio-Z data collected between two urination events to extract a single Bio-Z value for comparison, as depicted by the black squares in Fig. 4A.
  • Each averaged value was compared to the body weight measurement recorded at the preceding urination event.
  • the Bio-Z value extracted at the 45-minute mark obtained by averaging all Bio-Z data points between [42.5, 47.5] minutes, was directly compared to the body weight measurement result at 30 minutes.
  • Fig. 4C depicts the arm impedance normalized by arm diameter versus percent body weight loss for each participant.
  • Fig. 4E illustrates the per-participant height-normalized whole-body impedance versus percent body weight loss. Similar to Fig. 4C, positive linear correlations were evident across all participants. In this case, however, Pearson’s correlation coefficients exhibited a broader range, spanning from 0.611 to 0.989. The mean correlation coefficient for the cohort was computed as 0.870 ⁇ 0.117, and the notable increase in variance, relative to its arm impedance counterpart, may be attributable to several reasons. First, whole-body impedance data is more susceptible to posture- related variations and captures substantial fluid shifts occurring in the gastrointestinal and other regions of the human body.
  • the conformability of the e-tattoo to the body and its localized sensing capabilities make it more robust in the presence of motion.
  • the arm sensing configuration is less susceptible to posture-related variations and does not capture any fluid shifts unrelated to those occurring in the underlying tissue of the brachium.
  • BIVA Whole-body hydration assessment as described herein involves the utilization of BIVA.
  • BIVA uses whole-body resistance and reactance values, normalized for standing height and plotted on the RX C graph.
  • the resulting vector has both length and direction.
  • the length of the vector is inversely related to TBW, while the combination of vector length and direction serve as an indicator of tissue hydration status.
  • BIVA enables classification and ranking of hydration, along with soft-tissue mass, by analyzing an individual vector’ s position relative to a healthy reference population.
  • the variability among individuals in terms of impedance vector is depicted through a bivariate normal distribution with elliptical probability regions (50, 75, and 95%).
  • Vector position on the RX C graph is interpreted relative to the two directions on the RX C plane.
  • Vector displacements along the major axis of the tolerance ellipse signify progressive alterations in tissue hydration; dehydration is indicated by lengthy vectors outside the upper region of the 50% tolerance ellipse, while fluid overload with apparent edema is characterized by short vectors outside the lower pole of the 50% ellipse.
  • FIG. 4D illustrates paired vectors for each participant, where one vector indicates the participant’s status at the initiation of the protocol, and the other vector indicates the participant’ s status at the conclusion of the protocol.
  • discernible alterations in the RX C vectors were observed for all participants.
  • the directional shifts in the vectors for all participants, except participant 8 were consistent with trends associated with the loss of body water and previous literature utilizing whole-body impedance. Specifically, these changes were characterized by an upward and rightward displacement of resistance and reactance values.
  • participant 8 the arm impedance BIVA plot exhibited inconsistent directional changes, attributed to minimal changes in reactance over the course of the protocol. Participant 8’s reactance demonstrated relative stability throughout the protocol, while their resistance exhibited trends comparable to those observed in the other participants.
  • Figure 4F displays paired vectors representing each participant, using their gathered whole-body impedance data. Similar patterns are evident compared to the arm impedance data, highlighting the inherent capability of arm impedance to monitor hydration status. Moreover, as arm impedance data was continuously collected and BIVA does not necessitate body weight assessment, vectors can be plotted for any given time point, offering a temporally relevant portrayal of hydration status. The benefit of depicting arm impedance and whole-body impedance vectors at various protocol stages using the BIVA plot is that it demonstrates vector displacement toward an increasingly dehydrated state over time (see Figs. 4G - 4N). Figs. 4G - 4N each illustrates a BIVA plot for an individual participant corresponding to discrete measurements shown in Fig. 4A for arm impedance and whole -body impedance data. More transparent data points represent a more dehydrated state.
  • markers in the third quadrant indicate fluid overload and markers in the first quadrant indicate a dehydrated state.
  • the length of the BIVA vector from the starting marker to the end marker can be inversely related to the loss of TBW [47], with shorter vectors indicating minor fluid loss/gain while longer vectors suggesting a larger shift in hydration status.
  • Figure 5A presents the bioimpedance data plotted against time for the 24-hour daily living experiment. Body weight measurements were collected using commercial bath scales following any major activity or whenever the participant urinated, ate food, or drank a beverage. The graph delineates various activities, such as sleep, bus travel, and major meal consumption, aiming to elucidate patterns and trends within the data. To account for the common usage of medications in individuals’ daily routines, the diuretic-induced dehydration protocol, as previously discussed, was integrated into the 24-hour daily living protocol. Importantly, the participant’s dietary and fluid intake remained unrestricted, excluding the diuretic-induced dehydration period. Data collection encompassed the entire span of rehydration and food ingestion to capture pertinent information. The red 502 and blue 504 dashed lines in Fig. 5A correspond to the respective red 506 and blue 508 data points illustrated in Figures 5B and 5C.
  • Fig. 5B presents the BIVA plot for both the diuretic-induced dehydration and subsequent rehydration phases over the course of the 24-hour experimental protocol.
  • vector displacements consistent with dehydration and rehydration were observed; transitioning from a hydrated to a dehydrated state during diuretic-induced dehydration, and conversely, from a dehydrated to a more hydrated state as the participant underwent rehydration and ingested food.
  • a noteworthy observation pertains to the plateau observed in arm impedance several hours following the conclusion of the diuretic dehydration protocol.
  • Figs. 5E - 5H illustrate the outcomes of this repeated test, demonstrating a close alignment with the results depicted in Figs. 5A - 5D.
  • the rigid system exhibits more fluctuations in arm impedance data, as indicated by the large error bars. This variability is likely attributed to the system's rigidity, which impedes its ability to stretch or flex in response to the arm’s movements.
  • the participant reported electrode delamination around the 20-hour mark despite the absence of a notable spike in the data. This observation suggests that continued use could potentially lead to signal degradation.
  • Figs. 51 - 5L illustrate the diuretic-protocol results conducted using a single-side electrode configuration set up on two participants.
  • Fig. 51 illustrates the single-side electrode configuration setup using a hydration e-tattoo.
  • Fig. 5J illustrates post-processed arm resistance, reactance, and impedance data for the two participants undergoing the diuretic-dehydration protocol.
  • FIG. 5K illustrates a linear relationship between per-participant arm-diameter- normalized arm impedance and percent body weight loss.
  • Fig. 5L illustrates a BIVA plot for arm impedance data for the two participants.
  • Figs. 5M - 5P illustrate diuretic -protocol results conducted using a rigid wrist- worn cross-arm configuration setup on a single human participant.
  • Fig. 5M illustrates the cross-arm configuration setup.
  • Fig. 5B illustrates post-processed wrist resistance, reactance, and impedance data undergoing the diuretic-dehydration protocol. Large spikes in data can be due to sudden wrist movements.
  • Fig. 5C illustrates a linear relationship between wrist impedance and percent body weight loss.
  • Fig. 5D illustrates a serial BIVA plot for wrist impedance data, sselling displacement in line with a minor ellipse axis due to minimal reactance variations.
  • Fig. 5G illustrates a serial BIVA plot for wrist impedance data, sselling displacement in line with a minor ellipse axis due to minimal reactance variations.
  • 5Q illustrates a schematic representation of a sensing paradigm of the exemplary system. As shown, contact impedance decreases as a function of frequency (left).
  • Single-channel bioimpedance sensors e.g., MAX30002
  • Discussion #1 Water is vital for the human body as it constitutes 45-70% of human body mass, facilitates oxygen and nutrient transport, maintains proper organ function, regulates body temperature, eliminates waste, and supports virtually all other vital physiological processes
  • Dehydration defined as a deficit in total body water (TBW) can arise from inadequate fluid intake, excessive sweating, vomiting, and/or diarrhea [3].
  • Initial symptoms such as headache and dry mouth, can escalate to more serious conditions if left untreated.
  • the severity of dehydration can be quantified by the percentage change in total body weight caused by water loss.
  • life-threatening symptoms such as altered respiratory activity or various cardiovascular conditions (e.g., low blood pressure, elevated heart rate)
  • Considerable cognitive impairment has been observed to begin with a 2% reduction in body weight due to water loss [5], [6].
  • Dehydration also affects the thermoregulatory capacity of the body by decreasing sweating and cutaneous blood flow. For instance, core body temperature increases by 0.15-0.20 °C for every 1% decrease in body weight due to fluid loss [7]. Reduced thermoregulation increases the risk of developing heat-related injuries, such as muscle cramps, fatigue, or heatstroke [8]. Chronic mild dehydration is associated with an increased risk of kidney stone formation [9], [10].
  • Athletes are also susceptible to dehydration due to increased sweat production, which can exceed 1 L/h [3]. When combined with heat stress, dehydration impairs cognitive functions, athletic performance, and technical skills related to sports [12]. Even minor levels of dehydration can be critical, particularly at the elite level. Consequently, athletes, firefighters, and armed forces personnel would benefit from continuous hydration assessment to optimize performance, prevent injury, and aid recovery.
  • FIGS. 6 A - 6C each illustrates the conventional method for dehydration assessment.
  • Common practices for assessing dehydration typically involve qualitative methods, such as comparing the physical appearance of urine with a color chart (see Fig. 6A) [2].
  • these methods are susceptible to contamination (e.g., food, medicines) and human errors and are unsuitable for monitoring rapid changes in hydration status.
  • Quantitative assessment of a person’s whole body hydration (WBH) level relies on blood or urine tests, such as blood, plasma, or urine osmolality tests in labs (see Fig. 6B). Although these results are accurate, they are time-consuming and costly and only offer intermittent data points.
  • the lack of a real-time, mobile WBH assessment approach hinders decision-making and initiation of necessary rehydration measures.
  • Bioelectrical impedance i.e., bioimpedance signal, Bio-Z
  • Bio-Z provides a quantitative and non-invasive approach to evaluate WBH [2], [13].
  • Bio-Z capitalizes on the deep tissue penetration capability of alternating current (AC) to extract valuable physiological information and can distinguish between intracellular and extracellular fluids [14-16].
  • AC alternating current
  • the setup of commercial equipment for the detection of WBH involves placing electrodes on the hands and feet to measure the whole-body Bio-Z as the AC current flows through the body from hands to feet (Fig. 6C).
  • High-frequency AC can pass through both extracellular fluids (ECF) and intracellular fluids (ICF) (see Fig. 1C) [17].
  • ECF extracellular fluids
  • ICF intracellular fluids
  • Bio-Z analysis which uses multiple regression equations to predict fluid volumes, including TBW and extracellular water (ECW)
  • BIA Bio-Z analysis
  • ECW extracellular water
  • BIVA First introduced by Piccoli et al., uses the bivariate distribution of the whole-body electrical resistance and reactance recorded from a healthy reference population of 7722 males and 8181 females, known as the National Health and Nutrition Examination Survey III (NHANES III), to provide a qualitative indication of hydration, without any assumptions about body components or prediction models [22].
  • NHANES III National Health and Nutrition Examination Survey III
  • the BIVA approach is based on resistance and reactance measured from hands to feet or wrists to ankles, which limits its practicality for continuous ambulatory monitoring.
  • the potential of using localized deep tissue BIVA for the continuous assessment of WBH has never been explored due to the lack of suitable sensors.
  • the study introduced the exemplary system based on tetrapolar Bio-Z sensing with strategically placed electrodes across the arm (see Fig. 1A). Two pairs of temporary tattoo-like, skin-conformable electrodes for high-frequency AC injection and voltage sensing allow cross-arm Bio-Z measurement in the transmission mode (see Fig. IB). The measured resistance and reactance are wirelessly transmitted to a smartphone via Bluetooth Low Energy (BLE) in real time. To avoid complications in Bio-Z detection caused by temperature or motion, the study designed a diuretic- induced dehydration protocol that requires minimal movements and temperature fluctuation in an indoor setting (see Fig. IE).
  • the cross-arm Bio-Z and BIVA obtained by the exemplary system match the whole-body Bio-Z and BIVA measured by a state-of-the-art impedance analyzer.
  • the study also conducted a 24-hour measurement under free-living conditions (see Fig. IE).
  • the study demonstrated the feasibility and effectiveness of a crossarm Bio-Z sensor for continuous WBH assessment, improving awareness of hydration and facilitate proactive health management in everyday life or for high-risk and high-activity populations.
  • phase-sensitive RX C graph method that is based on the analysis of the bivariate distribution of the impedance vector in healthy populations, obese individuals, and individuals suffering from various renal diseases. Unlike BIA, BIVA does not rely on making assumptions about body composition [22].
  • BIVA is a noninvasive property-based diagnostic method used to assess body composition and hydration status by measuring the resistance (/?) and reactance (X c ) of biological tissue in a similar manner to BIA. Also similar to BIA, BIVA involves the application of electrodes to the arms and legs that pass a current through the body, with the resulting Bio-Z being a composite measure of both resistance, which reflects the opposition to current flow due to ICF and ECF, and reactance, which represents the capacitive properties of cell membranes. However, in contrast to BIA, BIVA considers the R and X ( components separately. The measured values are plotted on the RX C graph, providing a graphical representation that provides a qualitative indication of fluid distribution and body cell mass.
  • the RX C graph is constructed using a reference dataset and generates elliptical probability regions to qualitatively indicate hydration status and soft tissue composition.
  • the elliptical probability regions are generated using the standard reference interval of the NHANES III dataset [23] for healthy young individuals, as provided by Piccolli et al. (51 ).
  • NHANES III includes whole-body resistance and reactance recordings from approximately 15,900 adults derived from a 50-kHz signal, normalized for height to control for the different stature of individuals. Repeated RX C measurements, collected over long temporal durations, capture the intrasubject variability by using the intersubject variability of data from the reference population.
  • Discussion #3 A cohort of nine healthy participants, aged 19 to 29, participated in the diuretic-induced dehydration experiment in the study, while a single male, aged 26, was selected for the long-term daily living study. Participant selection considered diverse body mass index and musculature to explore their potential impact on the performance of the e-tattoo. Individuals who were selected to participate in the diuretic-induced experiment protocol were asked to refrain from drinking alcohol and caffeine 24 hours prior to data collection to prevent any external influence on hydration status. Following the completion of the study, participants were provided with an electrolyte solution (Pedialyte) to replenish lost fluids and restore electrolyte balance.
  • Pedialyte electrolyte solution
  • a wearable, bioimpedance-based, electronic tattoo capable of assessing whole-body hydration change in a non-invasive manner.
  • COMSOL FEM electrode configuration and spacing simulations, as well as experimental validation, were conducted for FPC layer design and optimizing bioimpedance sensitivity in underlying human tissue.
  • a diuretic-induced dehydration pilot study involving eight participants demonstrated the device’s applicability and heightened sensitivity for on-demand, wearable, and non-invasive whole-body hydration assessment. Results from a 24- hour daily living experiment further emphasized the device’s capability to capture both dehydration and rehydration trends on a single participant.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Surgery (AREA)
  • General Health & Medical Sciences (AREA)
  • Biophysics (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Physics & Mathematics (AREA)
  • Animal Behavior & Ethology (AREA)
  • Pathology (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dermatology (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)

Abstract

L'invention concerne un capteur de conception empilée, conformable et mobile qui, lorsqu'il est porté sur l'épiderme d'une personne, peut être utilisé pour détecter et surveiller en continu l'hydratation de l'ensemble du corps en temps réel comprenant un premier substrat isolant étirable flexible comprenant au moins deux électrodes d'injection de courant et une ou plusieurs électrodes de tension constituées de matériaux biocompatibles et formées sur un premier côté du substrat isolant étirable flexible et chaque électrode est configurée pour fléchir et s'étirer avec le substrat isolant étirable flexible.
PCT/US2025/022793 2024-04-15 2025-04-02 Tatouage électronique mobile et conforme pour la surveillance ambulatoire de l'hydratation de l'ensemble du corps Pending WO2025221460A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202463634140P 2024-04-15 2024-04-15
US63/634,140 2024-04-15

Publications (1)

Publication Number Publication Date
WO2025221460A1 true WO2025221460A1 (fr) 2025-10-23

Family

ID=97404105

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2025/022793 Pending WO2025221460A1 (fr) 2024-04-15 2025-04-02 Tatouage électronique mobile et conforme pour la surveillance ambulatoire de l'hydratation de l'ensemble du corps

Country Status (1)

Country Link
WO (1) WO2025221460A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4865039A (en) * 1985-08-21 1989-09-12 Spring Creek Institute Dry electrode system for detection of biopotentials and dry electrode for making electrical and mechanical connection to a living body
US20150005589A1 (en) * 2007-09-14 2015-01-01 Corventis, Inc. Adherent device with multiple physiological sensors
US20180020977A1 (en) * 2015-02-18 2018-01-25 The George Washington University Electrocardiogram sensor ring

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4865039A (en) * 1985-08-21 1989-09-12 Spring Creek Institute Dry electrode system for detection of biopotentials and dry electrode for making electrical and mechanical connection to a living body
US20150005589A1 (en) * 2007-09-14 2015-01-01 Corventis, Inc. Adherent device with multiple physiological sensors
US20180020977A1 (en) * 2015-02-18 2018-01-25 The George Washington University Electrocardiogram sensor ring

Similar Documents

Publication Publication Date Title
US9173615B2 (en) Method and apparatus for personalized physiologic parameters
US8688190B2 (en) Adherent device for sleep disordered breathing
AU2014274726B2 (en) Modular physiologic monitoring systems, kits, and methods
US11154204B2 (en) Simultaneous monitoring of ECG and bioimpedance via shared electrodes
US9662030B2 (en) Electrocardiography device for garments
CN113226448A (zh) 用于可穿戴电子数字治疗设备的方法和装置
WO2016030869A1 (fr) Répartiteur général sans fil multi-paramétrique pouvant être porté pour une surveillance de niveau d'hydratation
KR102691367B1 (ko) 생체 데이터 측정 장치
Scagliusi et al. Bioimpedance spectroscopy-based edema supervision wearable system for noninvasive monitoring of heart failure
CN215017678U (zh) 一种心脏康复监测装置
Medrano et al. Bioimpedance spectroscopy with textile electrodes for a continuous monitoring application
WO2025221460A1 (fr) Tatouage électronique mobile et conforme pour la surveillance ambulatoire de l'hydratation de l'ensemble du corps
Liu et al. Stretchable textile bands for ambulatory electrocardiogram and oximetry
US20160128639A1 (en) Graphical technique for detecting congestive heart failure
US11363997B1 (en) Electrode pads for bioimpedance
US20220142570A1 (en) System and method for a wearable device to measure and monitor human body vitals
Jankovic et al. Wireless Wearable E-Tattoo for Tracking Dehydration
Bandur et al. Designing a Wearable Wireless System for Real-time Bioimpedance Spectroscopy of Body Fluid
Jankovic et al. Wireless arm-worn bioimpedance sensor for continuous assessment of whole-body hydration
US20250241553A1 (en) Advanced wearable hydration monitoring system
Calzone et al. Innovations in biomedicine: Measuring physiological parameters becomes as simple as applying a plaster on the body
Ramos et al. A wireless sensor network for fat and hydration monitoring by bioimpedance analysis
Shengtong et al. A Wearable Breath Detection Device Based on Capacitive Coupling
Ausín et al. Live demonstration: A wireless multichannel bioimpedance spectrometer for patient monitoring
EP4299001A1 (fr) Dispositif portable, système et procédé de surveillance de l'état homéostatique

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25790277

Country of ref document: EP

Kind code of ref document: A1