Research

Urodynamics Monitor

Our lab developed a wireless, catheter-free pressure sensor—Urodynamics Monitor (UM)—to measure bladder behavior during normal filling. UM is quickly inserted and curls to remain in the bladder during recording. This device was licensed and led to the recent commercialization of the Glean Urodynamics System.

UroMOCA

Similarly to our work in colonic monitoring, our lab has focused on sensors for measuring bladder neurophysiology. To improve the translation of data from research to human clinical improvements, our lab developed a urological monitor of conscious activity (UroMOCA). The UroMOCA includes a pressure sensor and dual impedance-sensing electrodes for measuring bladder pressure and volume in awake animals.

ColoMOCA

To improve research in bowel neurophysiology, our lab produced a colon monitor to capture activity (ColoMOCA). ColoMOCA measures pressure wave propagation and stool impedance to detect motility. While ColoMOCA is currently a research tool used in large-animal research, it serves as a multi-modality, flexible sensor platform for future translation to human use.

High-Frequency IVUS

Intravascular ultrasound (IVUS) allows physicians to measure the internal anatomy and tissue properties of blood vessels and the heart. Our lab’s research in this field addresses the limited imaging resolution of current IVUS systems, while further expanding the capabilities of virtual histology. This will be accomplished by combining high frequency broad bandwidth (HFBB) polymer ultrasonic transducers with custom readout electronics which preserve the spectral features used by virtual histology.

Implanted Bladder Monitor

Conditional neuromodulation may enhance bladder neuromodulation while reducing stimulator power use, however, it requires feedback on organ activity. To enable continuous sensor feedback, we developed a real-time, wireless bladder pressure monitor. The implantable microsystem consists of an ultra-low-power application specific integrated circuit (ASIC), micro-electro-mechanical (MEMS) pressure sensor, RF antennas, and a miniature rechargeable battery.

Implanted Hemodynamic Sensor

Human tissues stretch far beyond the maximum range of metal strain sensors (about 3%). We have developed metal-free flexible pulsation sensors (FPS) capable of integrating with human tissue, for organ and vascular monitoring. These sensors use nanoparticles and/or nanotubes dispersed in medical elastomers to produce biocompatible strain sensors which can measure over 100% stretch. We integrate these sensors with implantable readout electronics. These new sensor form factors enable monitoring with reduced surgical complexity.

Non-invasive monitoring of blood flow

Many patients on hemodialysis rely on a vascular access to receive treatment; vascular access failure can cause a cascade of adverse outcomes. To improve early detection of at-risk individuals, we developed microphone sensor arrays to capture the sounds of turbulent blood flow within the vascular access. Because each microphone is small enough to pick up local sounds, by analyzing sound differences between microphones we can detect the location and severity of a vascular lesion.

Power- and Volume-Efficient Split Dipole / Quadrupole Canted Cosine-Theta (CCT) Antennas

The CCT design enables antenna integration while occupying a minimal volume within an implant, allowing smaller implant size or more space allocation to electronics and batteries. CCT coils are built on polyimide substrates, enabling them to wrap around thin cylinders, while inducing magnetic flux along axes transverse to the core. By incorporating a phase shift, additional magnetic polarization axes are added, which also makes these near-field antennas less directional.

The COSMIIC System

We are working with the Cleveland Open-Source Modular Implant Innovator’s Community (COSMIIC) to develop next-generation implantable neuromodulation systems. The COSMIIC System is one of two open-source medical devices, and the modular design with networked communication between modules enables rapid development of new functionalities. Our team is building tools for magnetic-field shaping and implantable radios that enable real-time sensor data streaming to the implant. More information: COSMIIC

Closed-Loop Sacral and Genital Nerve Stimulation

The peripheral nervous system interacts with organs using closed-loop (often reflexive) neural feedback pathways. When this feedback is disrupted (due to injury, illness, or aging), organ control is also affected. Urinary incontinence (UI) is a widely experienced example of peripheral organ dysfunction which affects a huge number of individuals worldwide. Our lab has several projects (combining bladder pressure sensors, real-time event detection algorithms, and nerve stimulators) which seek to “close the loop” and restore bladder function in humans.

Neuromodulation for Hypertension

Humans naturally regulate blood pressure using pressure-sensing nerves to relay blood pressure to the central nervous system constantly. We are working on an “electro-ceutical” option to provide treatment for the large number of people with drug-resistant hypertension. Our approach replicates this system using synthetic blood pressure sensors and neuromodulation to realize a fully implanted system for closed-loop control of blood pressure.

Ultrasonic Nerve Stimulation

Our lab is investigating the use of ultrasonic nerve stimulation (UNS) as a noninvasive, at-home treatment for pain or other conditions. First, we are producing flexible, wearable ultrasonic transducer arrays capable of generating acoustic intensities needed for nerve stimulation, with electronic beam-steering for nerve targeting. Second, we are studying how UNS activates or inhibits different sizes of axons in the sciatic nerve.

Bladder Pressure Event Classification

Bladder pressure is measured to diagnose urinary incontinence using catheters, and automated bladder event detection may enable sensor-based neuromodulation to control the bladder when it starts to contract. Our lab investigates how machine learning (artificial neural networks) and deep learning approaches can remove pressure artifacts or estimate what the bladder is doing in real time.

Phonoangiography

The sounds of turbulent blood flow due to vascular stenosis can be analyzed to describe the underlying lesion. Phonoangiograms (PAGs) are then formed using advanced signal processing and spatio-temporal detection. We have shown that PAGs estimate vascular stenosis and measure blood flow velocity based on acoustic phasing between recording sites. Our research in PAGs included 18-month trials with Veterans and reproduction of vascular sounds in calibrated phantoms on the bench.