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bioRxiv · 10.1101/2025.04.16.649006

Optically detected and radio wave-controlled spin chemistry in cryptochrome

Meng, K.·Nie, L.·Berger, J.·von Grafenstein, N. R.·Einholz, C.·Rizzato, R.·Schleicher, E.·Bucher, D. B.
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Abstract

Optically addressable spin systems, such as nitrogen-vacancy centers in diamond, have been widely studied for quantum sensing applications. In this work, we demonstrate that certain flavoproteins -- specifically cryptochrome and iLOV -- which generate spin correlated radical pairs upon optical excitation, also exhibit optically detected magnetic resonance (ODMR). Remarkably, the iLOV protein, commonly used in cellular imaging, displays ODMR contrast approaching 50%. We present initial applications including widefield magnetic field sensing and spatial modulation of photoluminescence using radiofrequency pulses and magnetic field gradients. Our results establish radical pairs in proteins as a novel platform for optically addressable spin systems, offering the key advantages of molecular designability and genetic encodability. Moreover, due to the spin-selective nature of radical pair chemistry, the results lay the groundwork for future radiofrequency-based manipulation of biological systems.

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Meng, K., Nie, L., Berger, J., von Grafenstein, N. R., Einholz, C., Rizzato, R., Schleicher, E., Bucher, D. B.. 2025-04-22. Optically detected and radio wave-controlled spin chemistry in cryptochrome. https://doi.org/10.1101/2025.04.16.649006

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