Thermal and Light-Induced Long-Range Electrodynamic Interactions Among Proteins Detected by Si-FET Biosensors

Using two complementary terahertz (THz) biosensing platforms based on silicon field-effect transistors (Si-FETs), we demonstrate that both light irradiation and thermal energy can trigger Fröhlich condensation and long-range electrodynamic interactions (LREIs) among proteins. Through a near-field lab-on-chip configuration, we identified two resonances as condensation fingerprints in the light-harvesting protein R-Phycoerythrin at 74 GHz (fundamental mode) – consistent with values already reported in the literature – and at 102 GHz (corresponding to the second-order mode). Moreover, we were able to monitor the evolution of the resonance quality factor ([Formula: see text]-factor) under illumination, revealing the dynamic modulation of protein collective modes. Complementary temperature-controlled THz spectroscopy further confirmed that these collective modes can also be thermally activated, with a clear temperature dependence of the fundamental mode. The consistency between the two experimental approaches highlights the versatility and sensitivity of Si-FET-based biosensors as quantitative probes of coherent electrodynamic phenomena in biomolecules, paving the way for label-free investigations of nonequilibrium biological dynamics under near-physiological conditions.