Event

Title: Hyperpolarized Spins: Quantum Sensing to Structural Biology

Abstract: I will present the development of electron and nuclear spin hyperpolarization techniques and their applications across diverse fields, including dynamic nuclear polarization (DNP), quantum sensing, chiral magnetic materials, and structural biology. With an improved understanding of the spin dynamics of chirped pulsed DNP [1], we performed experiments using the 94 GHz HiPER (High Power quasi-optical EPR) spectrometer located at the National High Magnetic Field Laboratory. Using chirped pulses, the polarization transfer efficiency can be optimized and a record enhancement ~ 496 was observed using 10mM trityl-OX063 as the polarizing agent in a standard d8-glycerol:D2O:H2O : 6:3:1 glassing matrix at 70K [2]. We believe that our experimental results at W-band are a strong evidence that coherent pulsed DNP methods should be further developed at higher magnetic fields, where the NMR resolution can be yielded and chirped DNP is one of the most promising techniques at high fields. Instead of relying on stable radicals, hyperpolarization of nuclear spins can also be achieved using photo-excited transient triplet states of pentacene molecules, known as triplet-DNP. We developed a neutron spin fillter based on triplet-DNP for polarized small-angle neutron scattering (SANS) experiments [3]. This development allowed us to study chiral magnetism induced by the Dzyaloshinskii-Moriya interaction (DMI) in a nanocrystalline two-phase alloy [4]. Moreover, the photo-addressability of pentacene molecules holds significant potential for quantum information science (QIS), inspiring us to explore the coherent control of these molecular spins through optical initialization and detection. In the final part, I will discuss how magnetic resonance techniques contribute to advancements in structural biology. Specially, we investigated the triple-helix structure of collagen peptides by combining spin-label electron{electron double resonance (DEER) EPR and NMR methods. This structural insight enabled us to develop collagen-mimetic peptides (CMPs) as probes for detecting damaged collagen [5].

Bio: Dr. Yifan Quan is a postdoctoral researcher at MIT in the Department of Chemistry and Francis Bitter Magnet Laboratory, working on hyperpolarization methods for nuclear magnetic resonance (NMR). Originally from China, Dr. Quan completed his undergraduate studies in physics at the University of Science and Technology of China in 2014. He then pursued a master degree at ETH Zurich, Switzerland, graduating in 2016, before starting his PhD at the Paul Scherrer Institute. Under the supervision of Dr. Patrick Hautle, Prof. Tom Wenckebach, and Prof. Michel Kenzelmann, he focused on the development of triplet dynamic nuclear polarization for polarized small-angle neutron scattering and obtained his PhD degree in physics in 2020. He subsequently joined the research group of Prof. Robert G. Griffin at MIT as a postdoc in 2021.