Development of wireless batteryless implantable blood pressure-EKG-core body temperature sensing microsystem for genetically engineered mice real time monitoring

Abstract

Two wireless implantable microsystems; one for blood pressure sensing and one for EKG and core body temperature sensing; are developed for untethered genetically engineered mice real-time monitoring. A flat silicone blood pressure sensing cuff and a low power ASIC are employed to form a novel wireless less-invasive blood pressure monitoring microsystem, which demonstrates a packaged system weight of 130 mg representing at least ten times mass reduction compared to any commercially available implantable blood pressure sensing technology. The system is powered by an adaptively controlled external RF energy source at 4 MHz to ensure a stable on-chip 2V supply with 150 µA current load from the microsystem, and achieves a sensing resolution of 0.8 mmHg. A packaged EKG and core body temperature sensing microsystem exhibits a total size of 9 mm × 7 mm × 3 mm with a weight of 400 mg including a pair of stainless steel EKG electrodes and demonstrates wireless in vivo EKG and body temperature sensing capability under the same adaptive RF powering condition. On-going research effort is devoted to realize a standalone wireless implantable three-channel (blood pressure, EKG, and core body temperature) bio-sensing microsystem.