UCLA

Magnetism is a workhouse for electric power generation at the macroscale, responsible for a large fraction of the electricity generation today. However, conventional approaches to energy conversion using magnets fail at a small scale due to Joule heating from electric currents. Recently, a method has emerged – room-temperature composite multiferroics coupling electrics and magnetics - that allows for control of magnetism via voltage as opposed to current. With this newfound capability, industrial & commercial application spaces are rapidly opening up for domains, including ultra-low-power spintronics devices, microwave devices, and even magnetic particle and cell sorting platforms. Meanwhile, personalized medical therapies hold the potential of new forms of highly effective therapies. One example of personalized medicine is CAR T-cell therapy, which uses patients’ cells for cancer treatments. However, such an approach requires technology that can analyze and sort these cells in high quantity, selecting only the cells that will be the most effective cancer fighters. Magnetic cell sorting is a popular approach for high throughput cell sorting. Still, there is no current method capable of capturing and culturing arrays of cells and then selectively releasing the desired ones. Recent advances in room-temperature multiferroic devices, such as devices where magnetism is controlled by electric fields, provide a path for capture, culture, and selective release of cells. However, work remains to understand how to manipulate the magnetic structures that capture these cells. This work aims to develop a multiferroics-based cell manipulation platform with high scalability and can achieve cell control locally. This work first conducts an in-depth study of the magnetization and multiferroic properties of various magnetostrictive layers, including Ni, FeGa, Ni/CoFeB, and Terfenol-D micromagnets on Pb(Mg1/3Nb2/3)O3]0.69[PbTiO3]0.31 (PMN-PT) piezoelectric substrates. It then selects the highly magnetostrictive Terfenol-D micromagnets in the same size scale as human cells as the candidate for life science applications. It also investigates the interaction between these micromagnets and cells before and after a voltage is applied across the PMN-PT substrate. The key questions addressed include how to create structures from a magnetoelastic material that are in the same size scale as human cells (20 \mu m) and control the magnetization of these structures to release cells on-demand via electric fields. Furthermore, this work demonstrates the potential of using patterned surface electrodes to generate localized strain in order to control the behavior of the micromagnets both locally and selectively.