Fig. 3

Silica nanoparticles (SiNPs). a Transmission electron microscopy images of mesoporous silica nanoparticles, acquired parallel (left) or perpendicular (right) to the long axis of the mesoporous channels. Reprinted from Ref. [57]. Copyright (2008), with permission from Elsevier. b Scanning electron microscopy image of neural stem cells (orange) grown on SiNP films (blue). Reproduced with permission from Ref. [61]. Copyright 2013 Nature Publishing Group. c Stereotaxic injection of SiNP-conjugated EGFP gene plasmids into mice brain. Left side image shows cells staining for EGFP in the substantia nigra. Right side image shows co-staining for transfected EGFP (green) and tyrosine hydrolase-positive dopaminergic neurons (red). Reproduced with permission from Ref. [63]. Copyright 2005 National Academy of Sciences, USA