Our multidisciplinary research group is focused on the design and development of state-of-the-art integrated circuits (analog, mixed-mode, RF, power management), wireless technologies, and complete systems for a wide range of applications such as healthcare monitoring, implantable medical devices, wireless neural interfacing, assistive technologies, wireless sensing and actuating, wireless power/data transfer and energy harvesting. These multidisciplinary research activities will lead to innovative technologies, medical devices and self-powered wireless systems to better understand our nervous system, help people with severe disabilities and disorders, and eventually improve the life quality.
Our research involves activities from basic science to modeling, simulations, prototyping, measurements, and experiments on animals. Some of the ongoing research projects in the ICSL are listed below:
Wireless Implantable High-Resolution Gastric Electrical-Wave Recording/Stimulation System
Gastric dysrhythmias are the main source of several gastric disorders such as gastroparesis and functional dyspepsia that significantly reduce the ability of the stomach to empty its content, resulting in pain, bloating, and early satiety symptoms. High-resolution mapping of gastric electrical activity has shown potential to detect the mechanisms underlying gastric dysrhythmias by recording gastric slow waves. However, electrode wires that traverse the abdominal wall or a natural orifice pose risks of discomfort, dislodgement, or infection. We are presenting two different methods for implantable high-resolution gastric electrical-wave recording/stimulation. In project-1 (see the figure below), an inductively rechargeable, wireless, and implantable system is developed that is composed of an implantable system-on-chip (SoC) to record slow waves from multiple channels, and an external reader to recharge the SoC battery using a pair of coils and receive the SoC recorded data by backscattering.
[See C24 in publications]
The multi-channel inductively interrogated (power/data) system can suffer from motion artifacts (noisy signal acquisition) and damage to the enteric nervous system due to its bulkiness (centimeter-sized), and also only acquires slow waves from a limited portion of the stomach. In project-2, we develop a network of distributed, minimally invasive (millimeter-sized), ultrasonically interrogated implants, called Gastric Seeds (see figure below), that are envisioned to be small (millimeter-sized), light, and wireless to minimize motion artifacts, tissue damage, and risk of infection and expulsion, and modular to acquire slow waves from the whole stomach through independent interrogation of each individual Gastric Seed with a specific address.
[See J30 and C34 in publications]
Sponsor: National Institutes of Health, NIH (NIBIB, SPARC Program)
High-Resolution Implantable Microscopic Ultrasound Neuromodulation
One of the grand neuroscience challenges in the 21st century is the minimally invasive stimulation of the whole brain (large scale) with high spatiotemporal resolution. Current neuromodulation methods, such as transcranial magnetic stimulation, electrical stimulation, optogenetics, etc., suffer from a tradeoff: either they provide large spatial coverage noninvasively while yielding a poor spatial resolution of several millimeters or more, or they provide sub- millimeter resolution while yielding a limited coverage of hundreds of neurons through extremely invasive parenchymal implantation. In this project we propose and develop focused and microscopic ultrasound neuromodulation platforms to provide large spatial coverage (whole brain), fine spatial resolution (sub-millimeter) and minimal invasiveness!
[See J31 and C29, C36 in publications]
Sponsor: National Institutes of Health, NIH (BRAIN Initiative)
Assistive Technology: Eyelid Drive System (EDS) for Wireless Environmental Control
Persons with physical disabilities often rely on assistive technologies to help them perform everyday tasks particularly those who lack sufficient control of their arms or hands. In this project we develop the Eyelid Drive System (EDS), which safely utilizes inductive sensing to create waveforms corresponding to the movements of the user’s eyelids (blinking and winking). The EDS overcomes many of the limitations of other assistive technologies: functional in any lighting condition, detects natural non-exaggerated blinks and winks, avoids the use of obtrusive patch electrodes on the face, fully portable and wearable, easy to calibrate, inexpensive.
[See J28 in publications]
Integrated Power Management for Wireless Power Transfer and Energy Harvesting
In this project, we develop novel integrated power management ASICs for inductive/ultrasonic wireless power transfer as well as energy harvesting (particularly from human motion). Our goal is to enable “smart” power management ASICs that will be capable of adaptively and dynamically reconfiguring their structures to compensate for environmental and electronic variations such as coils/transducers distance, alignment, and orientation changes, resonant frequency changes, load changes, etc. Our other objective is to harvest energy from weak multi-axial human motion using a custom inertial harvester with multiple flexible beams to enable wearables with 24/7 operation for vigilant healthcare monitoring.
[See J25, 26, 29 and C25, 27, 30 in publications]
Sponsor: National Science Foundation, NSF (ASSIST)
Towards Internet of Implantable Things: A Micro-scale Magnetoelectric Intra-body Communication Platform
The main objective of this project is to enable wideband, long-range, and low-power wireless communication among a network of miniaturized biomedical implants through the use of magnetic fields coupled with implantable micro-scale magnetoelectric (ME) transducers to ultimately enable the development of Internet of Implantable Things (IoIT). The specific research objective of this project is to tackle one of the primary problems facing current intra-body communication techniques: simultaneously providing high data rate (several Megabits per second, Mbps) and large communication range (within whole body) with low power consumption while dramatically reducing size (to millimeter) or invasiveness of the implant.
[See xx in publications]
Sponsor: National Science Foundation, NSF
Towards Wearable Closed-Loop Neural Mass Model Platforms with In-Situ Data Assimilation
In recent decades, dynamical mathematical models of subsystems within the brain—called neural mass models (NMMs)—have been used to gain insight into how different parts of the brain interact with each other. Data assimilation methods can synchronize a NMM to sparse or noisy measurements of neural firing rates. In this project, we plan to move data assimilation from a desktop computer to a system that is small enough and light enough to be mounted on an animal’s head in order to estimate neural firing rates in difficult-to-measure parts of the brain in real time. Real-time, in situ data assimilation of neural firing rates would greatly aid research into epilepsy, sleep dysfunction, and a variety of other neurological disorders. Furthermore, it would enable more sophisticated, highly targeted feedback to localized regions of the brain for the treatment of neurological diseases.
[See xx in publications]
Wireless (Inductive/Ultrasonic) Power/Data Transfer to Miniaturized Biomedical Implants
Wireless power transmission (WPT) to biomedical implants can eliminate their need for bulky batteries, increase their longevity, and reduce their size and risks. During the past few decades, inductive links have been the most attractive and efficient method for WPT to biomedical implants. This technique can offer high power transmission efficiency, particularly when the implant size is within centimeter dimensions. By miniaturizing biomedical implants to millimeter scales, minimally invasive biosensing and localized operations such as multisite neural recording, stimulation, and even optogenetics can be achieved. Millimeter-scale implants can also minimize the tissue damage and increase the safety and longevity of the neural interface. In this project we explore, design and develop inductive, ultrasonic and hybrid (inductive-ultrasonic) WPT links for powering millimeter-scale biomedical implants. Our main goal is to devise methods that are very efficient and robust against the movement of the implant, which is a key issue particularly in ultrasonic WPT.
[See J20, 23, 24, 27 in publications]