PhysiCell: An open source physics-based cell simulator for 3-D multicellular systems
Director cells (green) release a chemoattractant c1 to guide worker cells (red). Cargo cells (blue) release a separate chemoattractant c2. Unadhered worker cells chemotax towards ∇c2, test for contact with cargo cells, form adhesive bonds, and then pull them towards the directors by following ∇c1. If c1 exceeds a threshold, the worker cells release the cargo and return to seek more cargo cells, repeating the cycle. Bar: 200 μm. A video is available at S5 Video.