Intercellular cleft conductivity and tissue model with ID nanodomains. (A) Partitioning of the FEM mesh into 200 partitions or compartments, with different colors denoting different compartments. Overlaid on the mesh is a partial sketch of the reduced electrical network. (B) Example of adjacent partitions remeshing for equivalent conductance calculation. Partition centroids (orange circles), connecting line (solid black line), and cut lines (dashed black lines) are shown. (C) Solution to Laplace’s equation (Eq. 1) on the shared volume. (D) Resulting reduced electrical network for 200 nodes and the corresponding connections between adjacent partitions. Connection thickness is proportional to the conductance value, and edges in plicate or interplicate regions are shown as orange and blue, respectively. (E) Solution to Laplace’s equation on the full-cleft FEM mesh. (F) Comparison between voltages on the full-cleft FEM mesh and reduced network results. (G) Schematic of the electrical circuit (Eq. S2) and illustration of the corresponding electrical network at the ID, equivalent to the network shown in D.