Projects
Smart-Pill Tracking in the Gut
Localization and tracking of ingestible smart-pills in the GI tract is valuable for the diagnosis and treatment of GI disorders. In this project, we have developed a system for wireless 3D tracking of such smart-pills in the GI tract of large animals in real time and with millimeter-scale resolution. This is achieved by generating 3D magnetic field gradients in the GI field-of-view using high-efficiency planar electromagnetic coils that encode each spatial point with a distinct magnetic field magnitude. The field magnitude is measured and transmitted by the miniaturized, low-power and wireless smart-pills to decode their location as they travel through the GI tract. This system could be highly useful in monitoring constipation, incontinence, quantitative assessment of the GI transit-time, precision targeting of therapeutic interventions, and minimally invasive procedures.
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Link to Nature Electronics journal article here.
Link to Nature blog here.
Wireless Surgical Navigation
In this project, we developed a radiation-free system for high-precision surgical alignment, navigation and tracking of sensors and surgical tools used during various precision surgeries. We achieved this by generating 3D magnetic field gradients in the desired field-of-view such that each spatial point corresponds to a unique magnetic field value. Highly miniaturized, wireless and battery-less devices, capable of measuring their local magnetic field, are designed to sense the gradient field. One such device can be attached to an implant inside the body and another to a surgical tool, such that both can simultaneously measure and communicate the magnetic field at their respective locations to an external display receiver. The system is tested extensively to demonstrate one of the highest reported localization accuracy of <100μm in 3D. Our system can eliminate the harmful and ionizing X-ray radiation used during precision surgeries for tracking surgical tools and implants.
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Link to IEEE Transactions on Medical Imaging journal article here.
Link to IEEE International Solid-State Circuits Conference - (ISSCC) article here.
3D CMOS Magnetic Sensor
Magnetic sensors are used extensively in applications related to automotives, navigation, medical electronics and consumer products. Hall sensors are commonly used due to their compatibility with CMOS, but suffer from poor sensitivity and high power consumption. We present a new 3D magnetic sensor in the standard CMOS process with high sensitivity and ultra-low power operation. The sensor is comprised of three orthogonal and highly dense metal coils, which generate a voltage in response to AC magnetic fields by electromagnetic induction. The voltage signal is processed by on-chip circuitry that performs low-noise amplification, filtering, peak detection and digitization while consuming only 14.8µW to yield µT-level sensitivity. Though the sensor can be used for a variety of applications that require AC field sensing, it is particularly useful for biomedical applications - tracking catheters and guidewires during endovascular procedures, minimally invasive surgeries, targeted radiotherapy, and for use as fiducial markers during preoperative planning.
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Link to IEEE Custom Integrated Circuits Conference - (CICC) article here.
Wearable Biosensor for Fatigue Monitoring
To monitor the health and performance of military forces amidst drastic weather, lack of resources, unsanitary conditions and exotic diseases, we propose a wearable biosensor patch. By monitoring three categories of biomarkers from human sweat including metabolic biomarkers, vital signs parameters and immune response biomarkers using our wearable biosensor and analyzing the data with machine learning, we could predict the levels of fatigue with high accuracy in real time. This could provide crucial insight into the fatigue level of military forces, sailors and sportspersons, and result in significant benefits in improving performance, risk management and injury prevention. Currently working on the design of the sensor patch comprising a high-performance low-power IC chip that has functionalities for multi-channel signal acquisition, data processing (chopping, amplification, filtering, digitization) and wireless data communication. The final step would be to perform in vivo validation in human subjects.
CMOS Fluorescence Sensor
Integrating silicon chips and live bacterial biosensors in a miniaturized “Cell-Silicon” system can enable a wide range of applications in smart medicine and environmental sensing. Such integrated systems need on-chip optical filtering in the wavelength range compatible with fluorescent proteins, which are a widely used signal reporter for bacterial biosensors. However, the operating range of prior works falls short in detecting the fluorescent protein signals. In this work, we report a fully integrated fluorescence sensor in 65nm standard CMOS comprising on-chip bandpass optical filters, photodiodes, and processing circuitry. The sensor can measure the dynamics of the fluorescence signal as well as the growth of living E. coli bacterial cells. Using optogenetic control, a proof of concept is demonstrated to establish bidirectional communication between living cells and the CMOS chip. This integrated system creates a promising platform for the development of future closed-loop therapeutics.
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Link to IEEE Journal of Solid-State Circuits article here.
Link to IEEE International Solid-State Circuits Conference - (ISSCC) article here.
