In-Vitro Demonstration of Ultra-Reliable, Wireless and Batteryless Implanted Intracranial Sensors Operated on Loci of Exceptional Points

• Published in: IEEE transactions on biomedical circuits and systems Vol. 16; no. 2; pp. 287 - 295
• Main Authors: Yang, Minye, Ye, Zhilu, Alsaab, Nabeel, Farhat, Mohamed, Chen, Pai-Yen
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.04.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antennas; Biomedical measurement; Biomedical telemetry; Biotelemetry; biotelemetry and wireless sensing; Coils; Data acquisition; Electronic systems; Humans; Intracranial Pressure; intracranial pressure (ICP) monitoring; Loci; Micromachining; Misalignment; Monitoring; Monitoring, Physiologic - methods; Pressure; Prostheses and Implants; PT-symmetry; Radio frequency; Radio signals; Radio transmission; Remote monitoring; Reproducibility of Results; Sensor systems; Sensors; Signal monitoring; Telemedicine; Vital Signs; Wireless communication; Wireless sensor networks; Wireless Technology; wireless vital sign monitoring
• ISSN: 1932-4545; 1940-9990; 1940-9990
• DOI: 10.1109/TBCAS.2022.3164697

Vital signal monitoring, such as pulse, respiration rate, intra-organ and intra-vascular pressure, can provide important information for determination of clinic diagnosis, treatments, and surgical protocols. Nowadays, micromachined bioimplants, equipped with antennas for converting bio-signals to modulated radio transmissions, may allow remote continuous monitoring of patients' vital signs. Yet, current passive biotelemetry techniques usually suffer from poor signal reproducibility and robustness in light of inevitable misalignment between transmitting and receiving antennas. Here, we seek to address this long-existing challenge and to robustly acquire information from a passive wireless intracranial pressure (or brain pressure) sensor by introducing a novel, high-performance biotelemetry system. In spite of variable inductive links, this biotelemetry system may have absolute accuracy by leveraging the uniqueness of loci of exceptional points (EPs) in non-Hermitian radio-frequency (RF) electronic systems with parity-time ( PT ) symmetry. Our in-vitro experimental demonstration shows that the proposed intracranial (ICP) monitoring system can provide a sub-mmHg resolution in the ICP range of 0-20 mmHg and ultra-robust wireless data acquisition against the misalignment-induced weakening of inductive link. Our results could provide a practical pathway toward reliable, real-time wireless monitoring of ICP, and other vital signals generated by bio-implants and wearables.