fig1

Figure 1. A biosynchronized, transient and flexible regenerative peripheral neural interface (NeuroSyn). (A) Schematic diagram of the NeuroSyn; (B) Fabrication process of the device. The device is composed of PLLA-PTMC substrate (~120 μm, 8 mm × 25 mm), aligned PCL fibers (~30 μm, 8 mm × 10 mm) and sputtered Ti/Au electrodes (6 channels, ~10 nm/100 nm, 250 μm width, 1 mm spacing); (C and D) Photos of the device before and after rolling up; (E) SEM image of the surface morphology of the fiber electrode; (F) SEM image of the enlarged view of the fiber electrode, corresponding to the dashed red box in (E); (G) Optical image of the multi-channel fiber electrodes; (H) Representative confocal image of the guided neurite outgrowth of DRG neurons cultured on the fiber-based device on day 7. Immunohistochemical staining: axons (β-tubulin, green), Schwann cells (S100, red); (I) Quantitative analysis of DRG neuron’s axon alignment when cultured on PCL fiber films with varying concentrations; (J) Original impedance of the fiber electrodes. n = 3 samples, with 6 microelectrodes in each sample. Data are presented as mean ± SD; (K) Impedance of the fiber electrode at 1 kHz after immersion in PBS (pH 7.4, 37 °C) over a time frame of 68 days. n = 3 samples, with 6 microelectrodes in each sample; (L) Photos of the degradation process of the device at different stages in PBS (pH 7.4, 65 °C). The box plot presents the median (center line), lower quartile (lower border), upper quartile (upper border), maximum (upper whisker) and minimum (lower whisker), which are ≤ 1.5 times the interquartile range. PLLA-PTMC: Poly(L-lactic acid)-poly(trimethylene carbonate); PCL: polycaprolactone; SEM: scanning electron microscopy; DRG: dorsal root ganglion; SD: standard deviation; PBS: phosphate-buffered saline.