Measuring 3-dimensional dynamics of membrane in living cell with metal-induced energy transfer imaging/spectroscopy

The dynamics of cellular membranes are crucial for many essential cellular processes. Despite various methods available to study membrane dynamics, simultaneously measuring membrane diffusion and fluctuations within living cell membranes remains challenging. In this study, we developed a method combining metal-induced energy transfer (MIET) with fluorescence correlation spectroscopy (FCS) to accurately measure the three-dimensional (3D) dynamics of membranes, including transverse diffusion and vertical fluctuations. Our approach achieves a spatiotemporal resolution of one nanometer and few microseconds. We demonstrate the efficacy of our technique through experiments on the diffusion and transversal undulations of model membranes. Additionally, we showcase the versatility of MIET-FCS by applying it to various membrane systems within living cells, such as the plasma membrane, endoplasmic reticulum, and nuclear envelope. Our findings provide a powerful tool for investigating complex membrane dynamics in diverse cellular environments, advancing the field of membrane biophysics.