Figure 2. Characterization of electrospun polymer fibres and validation for support of iN differentiation.

(a,b) Scanning electron microscopy and (c,d) reflectance images of 2D fibrous and 3D electrospun pDTEc fibres, with substantially variable fibre architectures and porosities that respectively do not allow and allow cellular infiltration. (e) Schematic of RN-iPS cell reprogramming on 3D electrospun fibres. (f,g) RN-iPS reprogramming was carried out on 3D electrospun fibres, demonstrating that generation of βIII-tubulin and MAP2 positive iN cells on 3D electrospun fibres after 12 days proceeds similarly to 2D controls shown in Fig. 1. (h) Whole-cell current recordings demonstrate that iN cells cultured for 10 days on 3D electrospun fibres, 14 days total were predominantly electrically active with functional voltage-dependent Na⁺ channels, as well as voltage-dependent K⁺ channels, and (i) fire repetitive induced action potentials (n=18/20). Scale bar, 50 μm (c–d,f). Scale bar, 10 μm (g).