Fig. 1: Multi-scale simulations in systems biology.

a shows a schematic representation of an agent-based model of a 3D multicellular system in a microenvironment defined by the domain divided into fixed volumes together with examples of different intracellular models including signalling network, metabolism and cell cycle. b depicts examples of the different simulators and time scales for a multi-scale model including, the Δt_diff time scale where diffusion, uptake and secretion processes are updated; Δt_mec where the mechanics (movement and physical interactions) are updated; Δt_cell in which cell processes such as volume, cell cycle and death models are updated; and Δt_reg the regulatory time scale in which Boolean models are updated.