Though PPBI entails mostly facilities which specialize in optical imaging, some nodes do provide access to electron microscopy resources especially (but not limited to) projects which involve some form of correlative optical and electron microscopy (techniques generally known as CLEM - Correlative Light and Electron Microscopy, or 3D reconstruction of biological samples at EM resolution using "3D electron tomography". This possibility exists at nodes at IBMC, FCUL and IGC.