An Optical Implant for Biotelemetry: Design, in Vivo Verification, and Challenges

This article introduces a novel optical wireless framework that realizes linternet of Things (IoT) biotelemetry. For a clinical application, an implantable medical device (IMD) design is developed to capture in-body electrocardiogram (ECG) and transmit it through optical wireless communication to remote monitoring equipment. To achieve sub-milliwatt-level power consumption, a novel energy-saving strategy dedicated to the optical implants is implemented. Unlike existing RF-based IMDs, the optical IMD design allows seamless long-Term ECG monitoring with limited battery capacity, which elicits considerable diagnostic accuracy enhancement. In vivo experiments with canine models verify the viability of the IMD prototype for successful real-Time biotelemetry at the expense of only 384 μW along with its detection capability for various types of arrhythmic patterns. Important benefits of the optical IMD approach include the harmlessness of ultra-low-power optical emission to the living body as compared to the RF radiation of typical wireless IMDs prone to heat-generating dermal absorption, ending up with undesirable physiologic impacts. The optical IMD approach paves the way for an attractive IoT solution of biotelemetry applications.