PVDF and P(VDF-TrFE) Electrospun Scaffolds for Nerve Graft Engineering: A Comparative Study on Piezoelectric and Structural Properties, and In Vitro Biocompatibility

Abstract

Polyvinylidene fluoride (PVDF) and its copolymer with trifluoroethylene (P(VDF-TrFE)) are considered as promising biomaterials for supporting nerve regeneration because of their proven biocompatibility and piezoelectric properties that could stimulate cell ingrowth due to their electrical activity upon mechanical deformation. For the first time, this study reports on the comparative analysis of PVDF and P(VDF-TrFE) electrospun scaffolds in terms of structural and piezoelectric properties as well as their in vitro performance. A dynamic impact test machine was developed, validated, and utilised, to evaluate the generation of an electrical voltage upon the application of an impact load (varying load magnitude and frequency) onto the electrospun PVDF (15–20 wt%) and P(VDF-TrFE) (10–20 wt%) scaffolds. The cytotoxicity and in vitro performance of the scaffolds was evaluated with neonatal rat (nrSCs) and adult human Schwann cells (ahSCs). The neurite outgrowth behaviour from sensory rat dorsal root ganglion neurons cultured on the scaffolds was analysed qualitatively. The results showed (i) a significant increase of the β-phase content in the PVDF after electrospinning as well as a zeta potential similar to P(VDF-TrFE), (ii) a non-constant behaviour of the longitudinal piezoelectric strain constant d33, depending on the load and the load frequency, and (iii) biocompatibility with cultured Schwann cells and guiding properties for sensory neurite outgrowth. In summary, the electrospun PVDF-based scaffolds, representing piezoelectric activity, can be considered as promising materials for the development of artificial nerve conduits for the peripheral nerve injury repair.

Ti3C2Tx MXene-Coated Electrospun PCL Conduits for Enhancing Neurite Regeneration and Angiogenesis

“…The conductive MXene-PCL NGC could transmit physiological neural electrical signals, facilitate angiogenesis, and feed to stimulate nerve regeneration. Taken together, the MXene-PCL NGC revealed better effects in promoting nerve regeneration due to the cooperation of multiple other factors: a suitable mechanical support, affording a necessary lumen ( Gryshkov et al, 2021 ; Qian et al, 2021b ), conducting of nerve signals from upstream to downstream, and forming complete feedback. As shown in Figure 1 , the MXene-NGC could restore physiological nerve signal transduction from upstream to downstream and form complete biofeedback to the proximal and distal nerve stumps.…”

Frontier Electrospun Fibers for Nanomedical Applications

“…These polymers are known for their piezoelectricity which stimulates cells ingrowth induced by electrical activity upon mechanical force application. Having this in mind, the scaffolds showed biocompatibility with cultured SCs and supported sensory neurite outgrowth [104]. When layered double hydroxides (LDH) nanoclay particles were incorporated into electrospun PCL/gelatin, increased viability, and proliferation of the cultured human neuroblastoma SH-SY5Y cells were observed at higher LDHs, but there was no increased differentiation [105].…”

Effects of electroactive materials on nerve cell behaviors and applications in peripheral nerve repair

“…However, these types of piezoelectric ceramics are somewhat cytotoxic, which limits their application in peripheral nerve repair. Compared with piezoelectric ceramics, piezoelectric polymers have good biocompatibility and piezoelectric properties, for example, polyvinylidene fluoride (PVDF), 62,63 polylactic acid (PLLA), polyphenylene ester (PHB), collagen and its copolymer, 7,64,65 and are widely used in nerve repair (Fig. 2).…”