Quantum Sensing of Chiral-Induced Spin Selectivity: Elucidating the Relationships between Spin and Chirality in Biology with Diamond Defects

forthcoming

Photogenerated spin-correlated radical pairs (SCRPs) are electron spin pairs formed in well-defined spin states. Spin chemistry of SCRPs plays important roles in biology, as famously implicated in the leading hypothesis for avian magnetoreception. At the same time, synthetic molecules supporting SCRPs provide a versatile platform for quantum information applications with synthetic chemical tunability. Recently, significant interest in SCRPs in chiral (non-superimposable mirror image) systems has grown as systems to study mechanisms of chiral-induced spin selectivity (CISS), which describes spin-dependent interactions with chiral molecules like proteins at room temperature. However, the role of CISS in the spin dynamics of SCRP and physiological relevance of CISS in biological systems remain poorly understood and are significant open questions in both quantum science and modern biophysics. Quantum sensing of SCRPs using nitrogen-vacancy (NV) centers in diamond offers untapped potential to elucidate the complex spin dynamics of these systems and create a long-anticipated breakthrough in identifying the potential biological roles of CISS. In the proposed work of Q-CISS, novel quantum sensing experiments using single NV centers in nanophotonic diamond waveguides will be used to detect, measure, and manipulate photogenerated SCRPs at the single to few-molecule regime and at room temperature. First, this interdisciplinary approach will systematically build new knowledge by investigating well-defined synthetic achiral and chiral model systems. Second, key experiments are outlined to identify unambiguously the potential roles of CISS in SCRP dynamics in biological proteins hypothesized to be involved in avian magnetoreception. Collectively, Q-CISS will establish a unique approach to investigate combined roles of molecular chirality and spin physics in biological systems, while more broadly advancing room-temperature quantum sensing strategies for the chemical sciences.