Described herein are implantable devices configured to emit an electrical pulse. An exemplary implantable device includes an ultrasonic transducer configured to receive ultrasonic waves that power the implantable device and encode a trigger signal; a first electrode and a second electrode configured to be in electrical communication with a tissue and emit an electrical pulse to the tissue in response to the trigger signal; and an integrated circuit comprising an energy storage circuit. Also described are systems that include one or more implantable device and an interrogator configured to operate the one or more implantable devices. Further described is a closed loop system that includes a first device configured to detect a signal, an interrogator configured to emit a trigger signal in response to the detected signal, and an implantable device configured to emit an electrical pulse in response to receiving the trigger signal. Further described are computer systems useful for operating one or more implantable devices, as well as methods of electrically stimulating a tissue.

A system for deploying an electrode array at a target location through a hole formed in the patient's cranium. The system includes an array of electrodes attached to a substrate and an inserter attached to the substrate and/or the array of electrodes. The inserter, substrate and array of electrodes are configured into a first compressed state and are positioned within the lumen of a cannula. Using the cannula, the system is inserted through the hole, the cannula is then removed, and the inserter is used to transition the substrate and electrode array from the first compressed state to a second uncompressed state, thereby deploying the array of electrodes at the target location.

A catheter for electrophysiology includes a shaft extending along a longitudinal axis to a distal end and an end effector coupled to the distal end of the shaft. The end effector includes a first loop member disposed on a first side of the longitudinal axis, a second loop member disposed on a second side of the longitudinal axis, and a third loop member. The third loop member includes a first spine disposed on the first side of the longitudinal axis. The first spine includes a first plurality of electrodes. The first spine is positioned radially outwardly of the first loop member relative to the longitudinal axis. The third loop member further includes a second spine disposed on the second side of the longitudinal axis. The second spine includes a second plurality of electrodes and is positioned radially outwardly of the second loop member relative to the longitudinal axis.

A catheter for electrophysiology includes a shaft extending along a longitudinal axis to a distal end and an end effector coupled to the distal end of the shaft. The end effector includes a first loop member disposed on a first side of the longitudinal axis, a second loop member disposed on a second side of the longitudinal axis, and a third loop member. The third loop member includes a first spine disposed on the first side of the longitudinal axis. The first spine includes a first plurality of electrodes. The first spine is positioned radially outwardly of the first loop member relative to the longitudinal axis. The third loop member further includes a second spine disposed on the second side of the longitudinal axis. The second spine includes a second plurality of electrodes and is positioned radially outwardly of the second loop member relative to the longitudinal axis.

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.

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.

Described herein are implantable devices configured to detect an electrophysiological signal. Certain exemplary implantable devices comprise a first electrode and a second electrode configured to engage a tissue and detect an electrophysiological signal; an integrated circuit comprising a multi-transistor circuit and a modulation circuit configured to modulate a current based on the electrophysiological signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter encoding the electrophysiological signal from the tissue based on the modulated current. Also described herein are systems that include one or more implantable devices and an interrogator comprising one or more ultrasonic transducers configured to transit ultrasonic waves to the one or more implantable devices or receive ultrasonic backscatter from the one or more implantable devices. Further described are computer systems for operating one or more implantable devices, and methods of detecting an electrophysiological signal in a tissue.

Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation. Further described 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 describe are computer systems for operating implantable devices, methods of detecting radiation, methods of treating a solid cancer in a subject, and methods of monitoring a subject for recurrence of a solid cancer.

Described herein is an implantable device comprising a radiation-sensitive element (such as a transistor) configured to modulate a current as a function of radiation exposure to the transistor; and an ultrasonic device comprising an ultrasonic transducer configured to emit an ultrasonic backscatter that encodes the radiation exposure to the transistor. Further described herein is an implantable device comprising a radiation-sensitive element (such as a diode) configured to generate an electrical signal upon encountering radiation; an integrated circuit configured to receive the electrical signal and modulate a current based on the received electrical signal; and an ultrasonic transducer configured to emit an ultrasonic backscatter based on the modulated current encoding information relating to the encountered radiation. Further described 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 describe are computer systems for operating implantable devices, methods of detecting radiation, methods of treating a solid cancer in a subject, and methods of monitoring a subject for recurrence of a solid cancer.

A system for deploying an electrode array at a target location through a hole formed in the patient's cranium. The system includes an array of electrodes attached to a substrate and an inserter attached to the substrate and/or the array of electrodes. The inserter, substrate and array of electrodes are configured into a first compressed state and are positioned within the lumen of a cannula. Using the cannula, the system is inserted through the hole, the cannula is then removed, and the inserter is used to transition the substrate and electrode array from the first compressed state to a second uncompressed state, thereby deploying the array of electrodes at the target location.