Alumnus Kai Wu wins best poster at 2022 Joint MMM-INTERMAG

ECE alumnus Kai Wu is a recipient of the best poster award at the 15th Joint MMM-INTERMAG conference. He is one of only seven recipients chosen from among 500 participants. The poster is titled, “Handheld magnetic particle spectroscopy for rapid, one-step, wash-free detection of SARS-CoV-2 spike and nucleocapsid proteins in liquid phase.”

The research presented by Wu is particularly relevant as the world battles the COVID-19 pandemic caused by the SARS-CoV-2 virus. The poster reports a magnetic particle spectroscopy (MPS) platform for detection of the biomarkers of the virus, the spike and nucleocapsid proteins. This technique monitors the dynamic magnetic responses of magnetic nanoparticles (MNPs) and uses their higher harmonics as a measure of the nanoparticles’ binding states. By anchoring polyclonal antibodies onto MNP surfaces, these nanoparticles function as nanoprobes to specifically bind to target analytes (SARS-CoV-2 spike and nucleocapsid proteins in this instance), and form nanoparticle clusters. This binding event causes detectable changes in higher harmonics and allows for quantitative and qualitative detection of the target analytes in liquid phase. In addition to being highly sensitive, with faster turnaround times (the bioassay can be completed in five minutes), the platform combined with the one-step, wash-free, nanoparticle clustering-based assay method is versatile. Simply change the surface functional groups on the MNPs, and it allows for the detection of a variety of other disease biomarkers. In the light of how quickly COVID-19 spread, diagnostic tools that are accessible, rapid, and accurate are critical for disease control and surveillance. Traditional disease diagnostic methods such as qRT-PCR (quantitative reverse transcription-PCR) and ELISA (enzyme-linked immunosorbent assay) require multiple steps, trained technicians, and involve longer turnaround times, all of which can slowdown the tracking and control of disease spread.

Wu earned his doctoral degree in 2017. As a PhD student, Wu was a member of the Golden Gopher Magnetic Biosensing team, where he assisted in the development of a giant magnetoresistance (GMR) point-of-care device. In 2014, the team’s GMR handheld device won the Distinguished Award in the Nokia Sensing XCHALLENGE Competition. The technology was later transferred to a start-up company, Zepto Life Technology based in Saint Paul, MN. During this time, he independently developed a magnetic particle spectroscopy (MPS) platform from scratch, from the building of a benchtop system to perfecting the missing parts of the theory, which ultimately led to the successful detection of influenza A virus on the MPS benchtop system. 

Commenting on his experience building the MPS platform, Wu says: “My experience as a member of the Golden Gopher Magnetic Biosensing team was invaluable. I learnt the ropes of how to take a technology from the lab to the market. With Professor Jian-Ping Wang, I’m planning to form a start-up company based on our MPS portable device.”

MPS device development 

In 2019, he led a team comprising graduate and undergraduate students from ECE, and the departments of computer science and engineering, mechanical engineering, and chemical engineering and materials science to develop the poster award winning MPS point-of-care (POC) device for rapid, inexpensive, wash-free, and highly sensitive disease diagnosis. In 2020, he assisted Professor Jian-Ping Wang in securing federal funding from the National Institute of Food and Agriculture and the National Institutes of Health’s RADx-rad program. The funding was instrumental in helping the team build the first prototype MPS portable device the following year. In the same year they reported the MPS for the detection of SARS-CoV-2 spike and nucleocapsid proteins. Titled Team MagiCoil, it also includes faculty from ECE (Professor Jian-Ping Wang) and Veterinary Population Medicine (Professor Maxim C. Cheeran). Also in 2021, the team embarked on a collaboration with Aerosol Devices, Inc. of Colorado to develop a breathalyzer that would detect SARS-CoV-2 directly from exhaled breath, through joint funding supported by the National Institutes of Health’s RADx-rad program. The SARS-CoV-2 breathalyzer, which is functionally similar to breathalyzers used to determine blood alcohol level, could revolutionize COVID-19 control strategies by enabling non-specialists to screen individuals in high traffic spaces such as airports, large office buildings, and schools in near real-time. 

Other research

Another project Wu has been pursuing over two years now is the development of magnetic nanodevice arrays for the treatment of neurological diseases in collaboration with researchers from the Mayo Clinic. The goal is to develop an implantable magnetic nanodevice array that can generate a highly localized magnetic field for neuromodulation.

Last year, Wu  helped establish the Minnesota NeuroSpin Initiative, which will help connect neurologists, neuroscientists, and engineers to develop novel nanomagnetic materials and quantum spintronic devices for investigating and understanding the nervous system. 

Currently Wu is working on the synthesis of high-performance iron nitride (Fe₄N) nanoparticles to yield at-scale production of highly stable, and uniform gamma prime phase iron nitride (γ′-Fe₄N) nanoparticles suitable for biological and biomedical applications such as magnetic imaging, gene and drug delivery, magnetic hyperthermia therapy, magnetic separation, and magnetic biosensors. He is also working on micromagnetic modeling of the dynamic magnetizations of spintronic nanodevices at sub-micrometer scale, searching for new magnetic and spintronic devices for biomedical applications.

Dr. Kai Wu is a research associate on a team of scientists led by Distinguished McKnight University Professor and Robert F. Hartmann Chair Jian-Ping Wang’s group. After earning his PhD in 2017, he went on to complete his postdoc training in 2020, under the guidance of Wang. Learn more about Wu’s research.