IoMT-Enabled Stretchable Strain Sensor for Real-Time Urinary Bladder Monitoring

Abstract

urinary incontinence (UI), characterized by the loss of voluntary control over the urinary bladder muscles, significantly affects the patients’ quality of life. This study presents a novel, minimally invasive device-level solution for continuous urinary bladder pressure (UBP) monitoring, integrating advanced resistance-based strain sensor and antenna technologies with seamless Internet of Medical Things (IoMT) compatibility. A flexible ultrawideband (UWB) antenna with compact size of 6 mm × 7 mm × 1.5 mm is designed for biotelemetric communication. Additionally, a strain sensor was developed using a self-fabricated nonconventional conductive ink with silver nanoparticles, whereas both the antenna and sensor were printed on a Polydimethylsiloxane substrate. Performance of the antenna alone and the integrated antenna system is validated through experiments in saline solution and minced pork muscle. Operating at a center frequency of 2.45 GHz the antenna showed a measured −10 dB bandwidth of 3.23 GHz (1.40–4.63 GHz) with a measured gain value of −27.68 dBi. Moreover, the strain sensor exhibited a significant resistance change of approximately 420 kΩ from 0% to 90% stretching, showcasing its high sensitivity to minor pressure variations. Rigorous tests, including stretch-and-hold, repeated stretching, hysteresis loss measurement, and time response analysis, confirmed the accuracy and durability of the sensor. Furthermore, a wireless biotelemetric link was established, demonstrating the system’s ability to wirelessly monitor sensor data over distances exceeding 2 m. Finally, specific absorption rate and magnetic resonance imaging (MRI) compatibility analysis is evaluated to ensure safety of the system. This study underscores the potential of the proposed telemetry-enabled device to transform medical diagnostics, enhance patient outcomes, and redefine the management of UI within the rapidly advancing IoMT landscape, representing a significant advancement in smart healthcare.