A research team at the University of Tokyo has developed a new microscopy platform that can observe a previously hidden layer of biomolecular chemistry linked to weak magnetic fields. The work, led by Project Researcher Noboru Ikeya and Professor Jonathan R. Woodward at the Graduate School of Arts and Sciences, addresses a long-standing technical gap in life-science measurement: Many important intermediates in spin-dependent reactions are “dark” molecules that do not emit light directly and therefore escape conventional fluorescence imaging.
To solve this, the team combined two precisely timed light pulses with a synchronized nanosecond magnetic pulse. The approach, called pump-field-probe fluorescence microscopy, compares signals as the magnetic field switches at different points in time. This comparison isolates the spin-dependent part of the chemistry and reveals precisely how magnetically sensitive intermediates appear and disappear. The findings are published in the Journal of the American Chemical Society.
The researchers validated the method in flavin-based model systems that are widely used to study biologically relevant photochemistry. They showed that the platform can recover reaction lifetimes and magnetic responses with high sensitivity, including at low concentrations matching cellular conditions. The system was capable of detecting very small signal changes under practical low-damage single-experiment per frame settings, an important step toward future live-cell studies.
