Probing magnetic field effects on cellular redox state using autofluorescence intensity and lifetime microscopy

Weak magnetic fields affect a multitude of biological processes including cell metabolism and are hypothesized to be a result of magnetic field-sensitive spin-selective radical-pair reactions. To provide much needed visualization of this process, we demonstrate the use of a custom-built multimodal nonlinear optical imaging system capable of measuring the redox state of cells through multi-photon-excited autofluorescence and autofluorescence lifetime of metabolic cofactors. We demonstrate a custom multi-axis Helmholtz coil system to apply time-varying magnetic fields across the sample during imaging. This imaging platform allows for characterization and optimization of the effects of magnetic fields on live cells and tissues.