# US 10,118,054 B2 · Implants using ultrasonic backscatter for sensing physiological conditions

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- Number: US 10,118,054 B2
- Document ID: US10118054B2
- Status: Granted
- Kind: B2
- Application number: 15/702,301
- Filed: 2017-09-12
- Published: 2018-03-29
- Granted: 2018-11-06
- Earliest claimed: 2016-07-07
- Assignees: The Regents of the University of California
- Applicants: The Regents of the University of California
- Inventors: Michel M. Maharbiz; Jose M. Carmena; Mekhail Anwar; Burak A. Ozilgen; Dongjin Seo; Federica Fava
- Web page: https://patentgrep.com/patent/US10118054B2

## CPC

- A61B 5/0031: {Implanted circuitry}
- A61B 5/076: {Permanent implantation}
- A61B 5/279: specially adapted for particular uses
- A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)}
- A61B 6/4258: {for detecting non x-ray radiation, e.g. gamma radiation (A61B6/037 takes precedence)}
- A61B 8/00: Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B 8/04: Measuring blood pressure
- A61B 8/0808: {for diagnosis of the brain}
- A61B 8/085: {for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules}
- A61B 8/0875: {for diagnosis of bone}
- A61B 8/12: in body cavities or body tracts, e.g. by using catheters
- A61B 8/4483: {characterised by features of the ultrasound transducer}
- A61B 8/48: {Diagnostic techniques (A61B8/13 takes precedence)}
- A61B 8/56: {Details of data transmission or power supply}
- A61N 1/3605: {Implantable neurostimulators for stimulating central or peripheral nerve system}
- A61N 1/37205: {Microstimulators, e.g. implantable through a cannula}
- A61N 1/3787: {from an external energy source}
- B06B 1/06: operating with piezoelectric effect or with electrostriction (piezoelectric or electrostrictive devices per se H10N30/00)
- G01N 27/327: Biochemical electrodes {, e.g. electrical or mechanical details for in vitro measurements}
- A61B 2505/05: Surgical care
- A61B 2560/0219: of externally powered implanted units
- A61B 2562/028: Microscale sensors, e.g. electromechanical sensors [MEMS]
- A61B 2562/12: Manufacturing methods specially adapted for producing sensors for in-vivo measurements
- A61M 39/0208: {Subcutaneous access sites (implantable infusion devices A61M5/14276; transcutaneous access sites A61M39/0247)}
- A61M 2205/04: implanted
- A61M 2205/825: using mechanical generation of electricity, e.g. hand cranked generators
- A61N 1/0534: {Electrodes for deep brain stimulation}
- A61N 1/372: Arrangements in connection with the implantation of stimulators
- A61N 5/1071: {for verifying the dose delivered by the treatment plan}
- A61N 2005/1087: {Ions; Protons}
- A61N 2007/0021: {Neural system treatment}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

Described herein is an implantable device having a sensor configured to detect an amount of an analyte, a pH, a temperature, strain, or a pressure; and an ultrasonic transducer with a length of about 5 mm or less in the longest dimension, configured to receive current modulated based on the analyte amount, the pH, the temperature, or the pressure detected by the sensor, and emit an ultrasonic backscatter based on the received current. The implantable device can be implanted in a subject, such as an animal or a plant. Also described herein are systems including one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transmit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Also described are methods of detecting an amount of an analyte, a pH, a temperature, a strain, or a pressure.

## Claims

### Claim 1

A temperature-sensing system, comprising:
(a) an implantable device, comprising:
a temperature sensor configured to detect an internal body temperature; and
an ultrasonic transducer with a length of 5 mm or less in the longest dimension, the ultrasonic transducer configured to receive ultrasonic waves that power the implantable device, receive a current modulated based on the temperature detected by the sensor, and emit a temperature-dependent ultrasonic backscatter based on the current received by the ultrasonic transducer; and
(b) an interrogator comprising one or more ultrasonic transducers configured to transmit the ultrasonic waves that power the implantable device, and receive the temperature-dependent ultrasonic backscatter from the implantable device.

### Claim 2 (depends on 1)

The system of claim 1, wherein the ultrasonic transducer is a bulk piezoelectric transducer, a piezoelectric micro-machined ultrasonic transducer (PMUT) or a capacitive micro-machined ultrasonic transducer (CMUT).

### Claim 3 (depends on 1)

The system of claim 1, wherein the implantable device is 5 mm or less in length in the longest dimension.

### Claim 4 (depends on 1)

The system of claim 1, wherein the implantable device is implanted in a subject.

### Claim 5 (depends on 4)

The system of claim 4, wherein the subject is an animal or a plant.

### Claim 6 (depends on 1)

The system of claim 1, wherein the temperature sensor is a thermistor, a thermocouple, or a proportional to absolute temperature (PTAT) circuit.

### Claim 7 (depends on 1)

The system of claim 1, wherein the implantable device further comprises an integrated circuit.

### Claim 8 (depends on 7)

The system of claim 7, wherein the integrated circuit comprises one or more of a power circuit, a driver configured to provide current to the sensor, a front end configured to receive a signal from the sensor, or a digital circuit.

### Claim 9 (depends on 7)

The system of claim 7, wherein the integrated circuit comprises a digital circuit, and wherein the digital circuit is configured to operate a modulation circuit.

### Claim 10 (depends on 9)

The system of claim 9, wherein the digital circuit is configured to transmit a digitized signal to the modulation circuit, wherein the digitized signal is based on the detected temperature.

### Claim 11 (depends on 1)

The system of claim 1, wherein the implanted device is at least partially encapsulated by a biocompatible material.

### Claim 12 (depends on 1)

The system of claim 1, wherein the implantable device comprises two or more sensors.

### Claim 13 (depends on 1)

The system of claim 1, wherein the temperature sensor is a thermistor.

### Claim 14 (depends on 1)

The system of claim 1, wherein the temperature sensor is a thermocouple.

### Claim 15 (depends on 1)

The system of claim 1, wherein the temperature sensor is a proportional to absolute temperature (PTAT) circuit.

### Claim 16 (depends on 1)

The system of claim 1, wherein the system is configured to resolve 0.5° C. changes in temperature.

### Claim 17 (depends on 1)

The system of claim 1, wherein the volume of the implantable device is 5 mm3 or less.

### Claim 18 (depends on 1)

The system of claim 1, wherein the interrogator is configured to be wearable by a subject.

### Claim 19

A method of detecting a temperature, comprising:
powering one or more implantable devices implanted in a subject using ultrasonic waves emitted from an interrogator comprising one or more transducers, wherein the one or more implantable devices each comprise an ultrasonic transducer with a length of 5 mm or less in the longest dimension and a temperature sensor;
converting energy from the ultrasonic waves into an electrical current;
transmitting the electrical current to the temperature sensor;
measuring the temperature using the temperature sensor;
modulating the electrical current based on the measured temperature;
transducing the modulated electrical current into an ultrasonic backscatter that encodes the measured temperature;
emitting the ultrasonic backscatter to the interrogator; and
receiving the ultrasonic backscatter.

### Claim 20 (depends on 19)

The method of claim 19, wherein the one or more implantable devices are implanted in a subject.

### Claim 21 (depends on 20)

The method of claim 20, wherein the interrogator is worn by the subject.

### Claim 22 (depends on 19)

The method of claim 19, comprising analyzing the ultrasonic backscatter to determine the measured temperature.

### Claim 23 (depends on 22)

The method of claim 22, wherein 0.5° C. changes in temperature are resolved.

### Claim 24

A method of detecting a temperature, comprising:
powering one or more implantable devices implanted in a subject using ultrasonic waves emitted from an interrogator comprising one or more transducers, wherein the one or more implantable devices each comprise an ultrasonic transducer with a length of 5 mm or less in the longest dimension and a temperature sensor;
converting energy from the ultrasonic waves into an electrical current;
measuring the temperature using the temperature sensor;
modulating the electrical current based on the measured temperature;
transducing the modulated electrical current into an ultrasonic backscatter that encodes the measured temperature; and
emitting the ultrasonic backscatter to the interrogator; and
receiving the ultrasonic backscatter.

### Claim 25 (depends on 24)

The method of claim 24, wherein the one or more implantable devices are implanted in a subject.

### Claim 26 (depends on 25)

The method of claim 25, wherein the interrogator is worn by the subject.

### Claim 27 (depends on 24)

The method of claim 24, comprising analyzing the ultrasonic backscatter to determine the measured temperature.

### Claim 28 (depends on 27)

The method of claim 27, wherein 0.5° C. changes in temperature are resolved.