Figure 3.

Schematic showing the process of FBGC formation by macrophages responding to foreign particles of different sizes. Macrophages respond to foreign bodies in the host by (a) phagocytosis. However, when the particle is larger than a single macrophage, (b,e) they fuse to form multinucleated FBGCs around the particle, fully encapsulating it. (c,f) When the particle is much larger than an FBGC, multiple FBGCs attempt to fuse around the foreign particle to render extracellular degradation. (d–f) Haematoxylin and eosin staining of pig tissue implanted with degradable poly-ɛ-caprolactone nanofibres four weeks after implantation showing the formation of multinucleated FBGCs. (d) Low power view showing multiple regions of FBR to the degrading biomaterial. Black arrow: FBGC; pink arrow: degraded biomaterial foreign particle. (Online version in colour.)