Fig. 3 |. MorphE accommodates developmental growth for chronically stable neuromodulation, nerve growth monitoring and conduction velocity testing.

a, CSCc and impedance × area (at 1 kHz) for MorphE (n = 3) soaked in PBS at 37 °C for 8 weeks. The electrode size is 0.04 cm². Inset: schematics showing the MorphE immersed in PBS. b, Normalized resistance changes over 8-week implantation. The normalized nerve diameter was calculated based on the strain–resistance curve and compared to measured nerve diameter (n = 3 for week 0 to 4 and n = 4 for week 8). c, Amplitude of evoked CAP on a sciatic nerve with electrical stimulation (voltage amplitude varying from 50 to 500 mV for both cuff electrodes and MorphE). Monophasic pulse (200 μs) at 1 Hz was used. d, Representative trace of elicited CAP stimulated by MorphE and cuff electrode for 8 weeks. Blue dash denotes the 200 μs electrical stimulation pulse with amplitude of 300 mV. e, Amplitude of CAP change over time for both cuff electrodes and MorphE (week 0, P = 0.0011; week 2, P = 0.0002; week 4, P = 0.0006; week 8, P = 0.012). f, Conduction velocity measured by MorphE, cuff electrodes, compared to that of nonimplanted nerve in growing rats. n.m., not measurable due to device failure. MorphE versus nonimplanted leg (week 0, P = 0.42; week 2, P = 0.19; week 4, P = 0.08; week 8, P = 0.46). g, Image of cuff electrode and MorphE after 4-week implantation. The cuff electrode was outgrown and partially detached from the sciatic nerve. Scale bar, 1 mm. All error bars denote s.d. *P < 0.05; **P < 0.01; ***P < 0.001; NS, not significant; unpaired, two-tailed Student’s t-test was used for e and f, n = 7 (MorphE or cuff electrode) or n = 8 (sham control) for week 0 to week 4; n = 4 for week 8.