BPS2026 – Molecular biophysics: A quantum sensing approach

A vital step in decoding biomolecular mechanisms and functions is measuring their molecular dynamics—a challenge driving continuous development of new experimental techniques. Due to the diverse, intrinsic spin sources in biological systems (and the rich insight they provide), spin-based measurement methods have emerged as an attractive complement to conventional optical, mechanical, and electrochemical techniques. Quantum sensors provide a way to execute nanoscale spin-based measurements, combining the insight of magnetic resonance techniques with the sensitivity of fluorescent labels. Solid-state quantum sensors—such as the nitrogen-vacancy (NV) center in diamond—can reach single-molecule detection in magnetic resonance experiments of proteins and spin-labeled DNA duplexes. However, accessing the dynamics of these systems remains an outstanding challenge. Here, I will discuss how these quantum sensing approaches can be extended to access dynamics across decades of time. We have developed new experimental methods that simplify quantum sensing approaches while enabling us to access the spectral characteristics of stochastic signals, such as those pervasive in ion channel dynamics. Moreover, this new approach can be applied to many emerging classes of quantum sensors, such as small molecules and fluorescent proteins. Finally, I will discuss how magnetic fields—often overlooked in biophysics—are in fact a ubiquitous and information-rich sensing target, found in contexts from proton spins in biomolecules to capacitance fluctuations in membranes.