The tissue engineering field integrates smart materials, e.g. piezoelectric nanogenerators, leveraging mechanoelectric transduction for precise cellular control and tissue regeneration.[1] Our study introduces innovative piezoelectric scaffolds with controlled porosity and structure, employing gyroid surfaces from polydimethylsiloxane (PDMS) and sodium niobate (NaNbO₃). XRD diffractograms confirmed the conversion of the initial structure of NaNbO₃ into the piezoelectric orthorhombic perovskite phase. While, SEM and micro-computed tomography (μCT) analyses validated the even distribution and dispersion of NaNbO₃ within the PDMS matrix, revealing cubic morphologies (1.2 μm) (Figure 1a). Furthermore, μCT confirmed real porosity of scaffolds (18 and 63%). Subsequent cyclic compression tests of scaffolds, ranging from 12.5 to 50% deformation, revealed the beginning of permanent degradation for greater deformations (50%). After 100 cycles, the scaffold with the highest porosity (63%) demonstrated the highest loss of damping capacity (from 56 to 30%), while scaffolds with 18 and ~0% porosity exhibited more stability with losses of 5.65 and 2.25%, respectively (Figure 1b). High damping capacity is crucial in scaffold implant applications to reduce vibrations and the impact of mechanical shocks. The maximum compressive strength increased from 0.07 to 0.33 MPa, and Young's modulus increased from 0.0071 to 0.037 MPa with a decrease in porosity from 63 to ~0%, respectively (Figure 1b). Polarization of the scaffolds by corona plasma proved effective, as the open circuit voltage increased from 1.7 to 4.3 V (e.g. 63% porosity) with the applied electrical potential and mechanical stimulation (Figure 1c). The use of corona plasma offers advantages in the polarization of porous materials, increasing their electrical potential and charge accumulation in the pores. NaNbO₃ incorporation showed no cell toxicity (Figure 1e), and scaffolds with 18 and 63% porosity, containing NaNbO₃, enhanced cell proliferation more than PDMS-only scaffolds. Raman spectra and SEM-EDS images confirmed the mineralization of the piezoelectric scaffolds, demonstrating the potential use of this material for bone regions (Figure 1d). In summary, biocompatible piezoelectric scaffolds were developed with adjustable porosity, enabling the correlation of electrical output and mechanical compression damping. The sacrificial model construction approach effectively produced complex 3D scaffolds, advancing the performance of these materials for use in regenerative medicine.

References

[1] N, Goonoo; A, Bhaw-Luximon. Materials Today Chemistry, 2022, 31, 103491.