Research

UroMonitor

Our lab developed a wireless, catheter-free pressure sensor—UroMonitor—to measure bladder behavior during normal filling. UroMonitor is quickly inserted and curls to remain in the bladder during recording. This device is being commercialized while we continue to use it as a research tool in humans.

Collaborators: Margot Damaser PhD (Cleveland Clinic), Hui Zhu MD (Cleveland VAMC), Howard Goldman MD (Cleveland Clinic), Brian Kwon MD (University of British Columbia)

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.

Collaborators: Dennis Bourbeau PhD (The MetroHealth System), Margot Damaser PhD (Cleveland Clinic), Million Mulugeta DVM, PhD (UCLA), Muriel Larauche PhD (UCLA)

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.

Collaborators: Dennis Bourbeau PhD (The MetroHealth System), Margot Damaser PhD (Cleveland Clinic)

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.

Collaborators: Aaron Fleischman PhD (Cleveland Clinic), David Wilson PhD (CWRU), Russ Fedewa PhD (Cleveland Clinic), Geoff Vince PhD (Cleveland Clinic)

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.

Flexible Pulsation 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 flexible, wireless readout electronics (image shows example with double-helix antenna). These new sensor form factors enable monitoring with reduced surgical complexity.

Access AutoCheck

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.

Collaborators: Niraj Desai MD (Cleveland VAMC)

FootSafe

Persons with SCI who lack sensation of limb position are at risk for serious injury when driving power wheelchairs (PWCs) if their lower limbs become mispositioned. To prevent these avoidable lower limb injuries, we developed a foot position sensor and user alerting smartphone app, called FootSafe. FootSafe consists of an array of force and infrared distance sensors to measure the foot pressure on the footplate, and foot position in 3D space above the footplate. An iOS app running a foot detection algorithm notifies the user when they need to reposition their feet to prevent injury.

Collaborators: Kristi Henzel MD (Cleveland VAMC), Kath Bogie D Phil (CWRU SoM)

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.

Collaborators: Dennis Bourbeau PhD (The MetroHealth System), Margot Damaser PhD (Cleveland Clinic), Bradley Gill MD (Cleveland Clinic)

Ultrasonic Tibial Nerve Stimulation

Our lab is investigating the use of ultrasonic tibial nerve stimulation (UTNS) as a noninvasive, at-home treatment for overactive bladder. 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 UTNS activates different sizes of axons in the sciatic nerve, and how UTNS affects reflexive bladder activity in animals.

Collaborators: Margot Damaser PhD (Cleveland Clinic), Swarup Bhunia PhD (Univ. of Florida), Soumyajit Mandal PhD (Brookhaven National Lab)

Closed-Loop Hypertension Neuromodulation

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.

Collaborators: Jonathan Baskin MD (Cleveland VAMC), Dustin Tyler PhD (CWRU)

Phonoangiography

We are investigating flexible microphone arrays for capturing the sounds of turbulent blood flow due to vascular stenosis (see above). Using advanced signal processing and spatio-temporal detection, this sensor allows the creation of phonoangiograms (PAGs) to 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.

Bladder Pressure Event Classification

Bladder pressure is routinely 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 compressive sampling, bladder pressure feature extraction, and digital implementations of artificial neural networks to remove pressure artifacts or estimate what the bladder is doing in real time.