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Objective: Heart disease is the leading cause of death worldwide. Hypertension is an important precursor and the most common risk factor to heart failure. While some patients can control their high blood pressure with pharmaceuticals, many suffer from resistant hypertension, where antihypertensive medications do not achieve the desired outcome. Electrical stimulation is an emerging therapy to modulate blood pressure and integrating it with closed-loop feedback can improve blood pressure control. Methods: We design and fabricate two application-specific integrated circuits (ASICs) for stimulation and pressure sensing using TSMC's 180 nm MS RF G process. We create a closed-loop system by integrating the ASICs with a microscale pressure sensor and a custom-built Python script and test the full system in six Long Evans rats using vagus nerve stimulation. Results: After calibration and benchtop verification, we prove the functionality of the system in lowering, and maintaining a desired blood pressure in vivo. The system effectively monitors pressure and stimulates when that pressure exceeds the user-determined threshold. Conclusion: By combining this stimulation therapy with a pressure sensor, we present a novel closed-loop, electroceutical system that has the potential to monitor and modulate blood pressure. Significance: We present a drug-free, potentially side-effect-free electroceutical therapeutic for managing resistant hypertension. [ABSTRACT FROM AUTHOR]

Far-field RF powering is an attractive solution to the challenge of remotely powering devices implanted in living tissue. The purpose of this study is to characterize the peak obtainable power levels in a wireless myoelectric sensor implanted in a patient while maintaining safe local temperature and RF powering conditions. This can serve as a guide for the design of onboard electronics in related medical implants and provide motivation for more efficient power management strategies for implantable integrated circuits. Safe powering conditions and peak received power levels are established using a simplified theoretical analysis and Federal Communications Commission-established limits for radiating antennas. These conditions are subsequently affirmed and improved upon using the finite-element method and temperature modeling in bovine muscle. [ABSTRACT FROM PUBLISHER]

Objective:The goal of this paper is to create a large wireless powering arena for powering small devices implanted in freely behaving rodents. Methods: We design a cavity resonator based wireless power transfer (WPT) system and utilize our previously developed optimal impedance matching methodology to achieve effective WPT performance for operating sophisticated implantable devices, made with miniature receive coils (<8 mm in diameter), within a large volume (dimensions: 60.96 cm × 60.96 cm × 30 cm). We provide unique cavity design and construction methods which maintains electromagnetic performance of the cavity while promoting its utility as a large animal husbandry environment. In addition, we develop a biaxial receive resonator system to address device orientation insensitivity within the cavity environment. Functionality is demonstrated with chronic experiments involving rats implanted with our custom designed bioelectric recording device. Results: We demonstrate an average powering fidelity of 93.53% over nine recording sessions across nine weeks, indicating nearly continuous device operation for a freely behaving rat within the large cavity resonator space. Conclusion: We have developed and demonstrated a cavity resonator based WPT system for long term experiments involving freely behaving small animals. Significance: This cavity resonator based WPT system offers an effective and simple method for wirelessly powering miniaturized devices implanted in freely moving small animals within the largest space. [ABSTRACT FROM PUBLISHER]

This paper presents a fully wireless cardiac pressure sensing system. Food and Drug Administration (FDA) approved medical stents are explored as radiating structures to support simultaneous transcutaneous wireless telemetry and powering. An application-specific integrated circuit (ASIC), designed and fabricated using the Texas Instruments 130-nm CMOS process, enables wireless telemetry, remote powering, voltage regulation, and processing of pressure measurements from a microelectromechanical systems (MEMS) capacitive sensor. This paper demonstrates fully wireless-pressure-sensing functionality with an external 35-dB⋅m RF powering source across a distance of 10 cm. Measurements in a regulated pressure chamber demonstrate the ability of the cardiac system to achieve pressure resolutions of 0.5 mmHg over a range of 0-50 mmHg using a channel data-rate of 42.2 kb/s. [ABSTRACT FROM AUTHOR]