Fig. 1: Fully biodegradable and flexible piezoelectric nanofibers based on Rochelle salt (RS) and poly (L-lactic acid) (PLLA).

a Schematic illustration of the fully biodegradable piezoelectric PRSC composites for ultrasound-driven peripheral nerve regeneration and wireless colon peristalsis sensing. b SEM images of PLLA/RS nanofibers (PLLA to RS mass ratio of 4:1) and PLLA/RS after compression (PRSC), with EDS mapping demonstrating the presence of sodium and potassium from the RS crystals. c FTIR spectra of RS crystal powder (RS), electrospun PLLA nanofibers (PLLA) and PLLA/RS (4:1) nanofibers. a.u. in this figure and all subsequent figures represents arbitrary units. d XRD spectra of the PRSC nanofibers, PLLA/RS (4:1) nanofibers, solvent-casted PLLA/RS (4:1) films, RS crystal powders and PLLA nanofibers. e Pole diagrams of the (310) and (321) planes of RS crystals in different films, including solvent-casted PLLA/RS (4:1) films before and after compression, and PLLA/RS (4:1) nanofibers before and after compression. f Stress-strain curves of PLLA nanofibers, PLLA/RS nanofibers with different PLLA to RS mass ratios, and PRSC nanofibers. g Young’s modulus of different films. h Degradation process of the PRSC film in PBS at 65 °C, with the residual mass quantified at different time points. In g and h, the data are shown as mean ± s.d. In b–h, n = 3 independent experiments. n = 3 independent experiments. The SPSS software package (version 26.0) is used for the statistical analysis, followed by one-way ANOVA Tukey test (two-sided) (^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001).