  Biological cells are the prototypical example of active matter. Cells sense
and respond to mechanical, chemical and electrical environmental stimuli with a
range of behaviors, including dynamic changes in morphology and mechanical
properties, chemical uptake and secretion, cell differentiation, proliferation,
death, or migration.
  Modeling and simulation of such dynamic phenomena poses a number of
computational challenges. A modeling language to describe cellular dynamics
must be able to naturally represent complex intra and extra-cellular spatial
structures, and coupled mechanical, chemical and electrical processes. In order
to be useful to domain experts, a modeling language should be based on
concepts, terms and principles native to the problem domain. A compiler must
then be able to generate an executable model from this physically motivated
description. Finally, an executable model must efficiently calculate the time
evolution of such dynamic and inhomogeneous phenomena.
  We present a spatial hybrid systems modeling language, compiler and mesh-free
Lagrangian based simulation engine which will enable domain experts to define
models using natural, biologically motivated constructs and to simulate time
evolution of coupled cellular, mechanical and chemical processes acting on a
time varying number of cells and their environment.
