A) Hematoxylin & eosin stain of cells within the POC scaffold. B) Anti-EGFP stain for a POC scaffold containing EGFP plasmid. Positive cells stain green, cell nuclei stain red, C) Anti-EGFP stain for a POC scaffold containing the luciferase plasmid (no positive cells, cell nuclei stain red), D) Anti-F4/80 macrophage stain of a POC scaffold. Macrophages stain red, cell nuclei stain blue. S denotes the scaffold. Scale bar = 50 μm.