Minimal neuroblast/neuronal progenitor cells localized to injection. At day 7 post injection, little to no Dcx+ co-localization with CXCR4 was observed in response to any of the injection conditions, Vehicle (A, a), blank NPs (B, b), SDF-1 bolus (C, c), and SDF-1 NPs (D, d). Red = Dcx, Green = CXCR4, Blue = DAPI. (A-D) Scale bar = 100 μm; (a-d) scale bar = 20 μm.