Bioprinted Scaffold Cell Viability: Oxygen Diffusion & Necrotic Core

A freshly bioprinted tissue construct has no blood supply — every cell inside it survives on oxygen diffusing in from the surrounding culture medium until vascularization catches up. This simulator solves the steady-state spherical diffusion–reaction equation live on a radial grid, showing a cutaway of the construct where each cell is colored by its local oxygen concentration. Push the radius up, the consumption rate up, or the medium oxygen down, and watch a dark necrotic core appear at the centre exactly where the numbers predict it — the same diffusion-limited failure mode that makes vascular channels and perfusion bioreactors mandatory for anything thicker than a few hundred microns.