Crossing Disciplinary Borders with Dr. Kai Wu: Engineering in Medicine

For ECE alumnus and current postdoctoral research associate Kai Wu, moving from one accomplishment to the next has become a matter of habit. In keeping with his name (which means triumphant music in Mandarin), his academic and professional career has been ascending as it explores new frontiers in engineering in healthcare. 


Born in Jinhua, China, Kai was an exemplary student all through high school with dual interests: engineering and medicine. Torn between pursuing two disparate fields, after several discussions with his parents, Kai decided to pursue a bachelor’s degree in engineering. He graduated in 2013 from Northwestern Polytechnical University, Xi’an with a bachelor’s degree in electronics and information engineering. 

Keen on taking his academic interests further, he applied to the doctoral program in ECE, but his interest in the medical field had not diminished. But a conversation with Prof. Jian-Ping Wang ( Robert Hartmann Endowed Chair and Distinguished McKnight University), prior to arriving at the University, turned out to be an eye opener for him. Talking to him, Kai realized that it was indeed possible to marry his dual interests, and conduct interdisciplinary research where he could use his engineering expertise for advancements in the field of medicine.


For Kai, there were two key factors that brought him to the University: the nanofabrication facilities, and the opportunity to pursue interdisciplinary research. (Of course, the campus location on the banks of the Mississippi river was a close runner up!) Arriving at the University in 2013, he joined Prof. Wang’s research team, and has ever since been deeply entrenched in research located at the crossroads of nanotechnology, chemistry, biology, magnetic materials, and circuits.

Commenting on his work, Prof. Andres Perez, one of Kai’s advisors says: “Dr. Wu’s project is interdisciplinary, bridging three grand-challenge initiatives (namely, food system, water resources, and biosensors) with the ultimate objective of developing state-of-the art technology to protect the natural resources and food production in the state.”

Guided by Prof. Wang, as a doctoral student Kai also worked closely with professors Andres Perez and James Collins from the College of Veterinary Medicine, especially during the year of his interdisciplinary doctoral fellowship. The freedom to work across disciplines and engage with experts from different fields has afforded him the opportunity to learn about needs and challenges that exist in disparate fields such as veterinary science, food safety, and neurotherapy, while also developing his skills as an articulate communicator of his electrical engineering-based research to scientists with non-engineering backgrounds. 

Over the course of his graduate and postdoctoral career (Kai earned his doctoral degree in 2017), Kai has pursued multiple lines of research , each with the promise of direct real world applications. His work includes developing flexible spintronic nanodevice arrays for large-scale, high resolution brain stimulation and mapping, developing a portable, handheld GMR (giant magnetoresistive) platform for different bioassay applications, and developing a portable magnetic particle spectroscopy (MPS) device for immunoassay applications.

Praising Kai’s work, Prof. Walter C. Low, says: “ I had the distinct pleasure of serving on Dr. Kai Wu’s thesis committee. His PhD research was focused on fabricating magnetic nano-devices for immunoassay applications and required a solid understanding of areas such as nanotechnology, material science, electrical engineering, molecular biology, and immunology. He developed expertise in biology, biomedical engineering, and different immunoassay technologies through collaborations with researchers across the University. His ability to master all of these disciplines to carry out his doctoral thesis was quite impressive. ”


A key motivator for Kai has been knowing that many diseases can be managed and even cured if detected early. And early detection often depends on the wide availability of sensitive biomedical detection technologies. Currently, the most commonly used optical diagnostic technologies such as ELISA (enzyme-linked immunosorbent assay) are susceptible to biological noise, bulky in size, and long detection time. Kai is working on developing  point-of-care (POC) devices based on magnetic nanosensors to provide fast, accurate, and user-friendly laboratory molecular diagnostics. The goal is to make them available for in-home testing as well as online specimen monitoring on both mobile and laptop user interfaces.


Currently, Kai is focused on  the development of flexible spintronic nanodevice arrays for large-scale, high resolution brain stimulation and mapping. The effort contributes to the NIH Brain Initiative, where a critical goal is the development of new technologies for large-scale recording and modulation of brain activities with high spatial and temporal resolution. Kai is collaborating with professors Tay Netoff, Walter C. Low and Susan A. Keirstead, and Dr. Kendall H. Lee (an expert in deep brain stimulation at the Mayo Clinic) in this endeavor. They propose a completely new flexible Spintronic NanoDevice Array (SNDA) that could potentially stimulate and record the activity from every neuron within a functional column of cortex. As a first step towards the NIH goal, a project jointly undertaken by the University of Minnesota Twin Cities and the Mayo Clinic was funded earlier this month to the tune of $1 million. The funding comes from the Minnesota Partnership for Biotechnology and Medical Genomics. The project is titled, “Magnetic Nanodevice Arrays for the Treatment of Neurological Diseases” and will be led by Distinguished McKnight University Professor and Robert F. Hartmann Chair in Electrical Engineering, Jian-Ping Wang, along with His co-investigators are Dr. Kendall H. Lee (Mayo Clinic), and professors Tay Netoff and Walter C. Low from the University. 

Current technology uses electronic devices that are vulnerable to the encapsulation of brain cells, causing increased impedance and thereby affecting the effectiveness of the technique. The constant need to re-program currently available deep brain stimulation devices is a result of such effects. In contrast, stimulation using magnetic field is unaffected by the encapsulation of cells. In addition, the ability to fabricate magnetic spintronic nanodevices as sensors and stimulators allows for superb resolution in the area of brain stimulation,  and recording at the level of single cells, and potentially even at the synapse level. 

The team’s goal is to demonstrate the feasibility of neuron stimulation and recording using magnetic spintronic nanodevices, which no studies yet have demonstrated. While this proof-of-concept design includes a single flexible chip, dozens of chips could be run by the same electronics, and these  chips can be assembled to make 3-D arrays. Spintronic nanodevices offer several novel mechanisms which can be harnessed into new device paradigms that can drive progress in the sensing and modulation of neuron activities. 


Yet another project Kai is working on involves extending the capacity of giant magnetoresistance (GMR) biosensor arrays  to enable rapid on-site detection of multiple swine respiratory disease pathogens directly from clinical sample matrices using a portable device. A related effort is the development of a cost effective, portable handheld GMR platform for the multiplexed detection of foodborne listeria monocytogenes, and E. coli pathogens. The intent is to transform the current expensive, time consuming, and complicated sensing techniques into a user-friendly and cost-effective detection protocol with superior or at least comparable sensitivity and selectivity, which could contribute to the control and monitoring of foodborne pathogens. 


Research is often a collaborative endeavor, and the quality and health of academic discourse is determined by the effort invested by the authors, reviewers, and editors involved in the process. Their work is vital to their community, while simultaneously training them to be robust contributors to communication within the discipline or area. 

Since joining Prof. Wang’s research group in 2013, Kai has published over 30 peer-reviewed papers in journals including Small, ACS Applied Materials & Interfaces, and ACS Sensors. He has also authored a book chapter titled “Magnetic Nanoparticle-based Biosensing” in Clinical Applications of Magnetic Nanoparticles: From Fabrication to Clinical Applications (edited by N.T. Thanh).

Kai has been a steady contributor to the scientific community of his field, and has been a  guest editor for special issues of Magnetochemistry and Journal of Sensors. He has also contributed his time as a conference reviewer, and journal reviewer for several journals. 

Since 2014, Kai has been leading Prof. Wang’s Magnetic Biosensing team, working on the development and optimization of the GMR biosensing platform, and designing new bioassay methods. He is also actively collaborating with researchers from different areas to promote Z-Lab, a portable diagnostic platform for on site testing of biological samples for various ailments, and working on joint grant proposals with faculty from the University’s College of Veterinary Medicine.

Prof. Wang, Kai’s postdoctoral fellowship advisor, is keenly aware of his unique blend of talent and drive: “Kai is a unique PhD student. He is talented and hardworking and one of the most productive students in my group. He is methodical, has a clear objective, and can work on a problem day and night until it is solved. When Kai decides on a task, he aims at getting the best outcome. As a person, Kai is always pleasant and warm, and is a role model to my other team members. I am blessed to have Kai as part of my team.

Starting 2017 fall, he has been leading a group of doctoral students from Prof. Wang’s group, collaborating with professors from the departments of Biomedical Engineering, Neurosurgery, and  Integrative Biology and Physiology. The goal is to develop flexible spintronic nanodevice arrays for large-scale, high resolution brain stimulation and mapping. As a lead, Kai’s coordinates communication within and across the areas, designs nanodevices that meet neurology requirements, provides advice and train doctoral students new to the group, and writes grant proposals.

Extending his leadership and team player skills, Kai has been a mentor and lead to undergraduate students from the departments of ECE, computer science and engineering, and mechanical engineering, training them in the development of a portable magnetic particle spectroscopy (MPS) device for immunoassay applications. MPS is a promising, cheap bioassay platform that has the potential to be applied in both in vivo and in vitro diagnostics. Called MagiCoil v1.0, the device is designed to provide fast, accurate, and user-friendly laboratory molecular diagnostics, in-home testing, as well as online specimen monitoring on both mobile and laptop user interfaces. It is a battery driven, in-vitro, POC device with an e-diagnostic feature that is reusable and accessible for non-technicians. Magnetic nanoparticles (MNPs) with antibodies are preloaded in a small vial, and users can simply drop body fluids (blood, urine, etc.) into the vial when a real-time signal will be collected by the Magicoil system and sent by bluetooth to the user interface. Users can get the diagnosis result within 10 minutes. The portable test kit could be used for on-field bioassays in nanomedicine, food control, agriculture, and veterinary medicine. Kai has provided the students with direction on experiment design, technical expertise in the interpretation and analysis of lab data, and research oversight. 

Doctoral student Renata is a beneficiary of Kai’s mentoring skills: “I joined Prof. Wang’s research group in Fall 2018 but had known Kai and his outstanding work on magnetic bio-sensing since 2017, when I was applying to the graduate program. Working with Dr. Wu for more than a year, I learnt to think around new scientific ideas, and most importantly, how to demonstrate them in scientific writing. The first year of grad school research is undoubtedly challenging, but Kai always had my back. “


For Kai, the path he has taken has brought him the best of both worlds, engaging his interest in engineering and medicine. And he in turn has taken the opportunity to contribute his ideas and innovations towards undertakings that will have far-reaching consequences in the diagnosis and treatment of diseases. 

In keeping with his name (which incidentally also sounds like the Greek letter chi χ, which symbolizes magnetic susceptibility), Kai’s professional trajectory has moved from strength to strength. We wait with bated breath on what lies ahead. 

Learn more about Kai’s work