Before analyzing the scattering intensity changes during positive cell polarization, we first must consider the data from the ex situ SAXS of the empty and electrolyte filled nanoporous carbon (Fig. ). The scattering intensity of the nanoporous carbon can be split into three additive terms: one accounting for spatial correlations on the molecular level, called structure factor, a second one accounting for the spatial correlations of the nanopores, which we refer to as nanopore scattering, and a third one accounting for the scattering contribution of the AC particles (with a size around 1 µm) . Given the reciprocal relationship between the size of realspace objects and their appearance on the scattering curve, the structure factor contribution is most prominent at large scattering vectors q (large scattering angles). The nanopore scattering appears as a distinct intensity hump at intermediate scattering vectors q, with the shape and the position containing information about the pore morphology, size distribution, and mean pore size. The increased scattering intensity at q < 0.8 nm -1 is caused by the scattering of the AC particles. The nanopore scattering intensity depends on the squared electron density difference between pores and carbon skeleton; therefore, filling of the nanopores with electrolyte leads to a significant decrease of the scattering intensity (Fig. , inset). At the same time, the electrolyte structure factor increases the scattering intensity in the WAXS regime. The distinct intensity peak around 20 nm -1 can be attributed to the first water structure factor peak (Supplementary Fig. ).