The iPSC line was generated from skin fibroblasts of a healthy individual and was reprogrammed through retroviral expression of OCT4, SOX2, cMYC, KLF4 as described previously [22]. The line was characterized for expression of pluripotency markers (OCT4, Tra-1-60, SSEA4, Nanog), genomic integrity through G-banding karyotype analysis and teratoma analysis [22-23, 53]. iPSCs were cultured and maintained as described previously [22-23]. Differentiation of iPSCs into midbrain dopaminergic neurons was done according to published protocols [24]. To better control consistency of neuralization, cells were first passaged en bloc at day 10 to 15 by mechanical dissociation of thickened cell layer into 2mm2 blocks followed by plating onto PDL/laminin coated 10cm dishes. At day 25 to 30 of differentiation, neural blocks were passed by accutase treatment onto laminin coated micropatterned substrates (for details see above) and incubated until analysis. Neuralization growth factors were withdrawn at day 40 and neurons were maintained in Neurobasal media (Life Technologies, #21103-049) containing Neurocult SM1 supplement (Stemcell technologies, #05711). The medium was replaced every 3 days.
