All-Dielectric Metasurface-Enhanced Fluorescence for Probing Mitochondrial Membrane Potential Dynamics

Fluorescence probes are the primary tools for monitoring mitochondrial membrane potential (MMP), a key indicator of mitochondrial function and cellular health. Although metasurfaces offer significant potential for enhancing fluorescence biosensing, all-dielectric metasurfaces with their inherent advantages remain largely unexplored for this application. Here, we demonstrate a fluorescence probe for MMP dynamics, significantly enhanced by an all-dielectric metasurface. Designed to support bound states in the continuum (BICs) via folded Brillouin zones, this metasurface achieves both a high quality factor and strong near-field enhancement. Experiments reveal an order-of-magnitude fluorescence intensity enhancement for cells on the metasurface compared to those off it, irrespective of forskolin stimulation. This approach enables dynamic monitoring of cellular health through MMP fluctuations at subthreshold concentrations.