Protocol and cell responses in three-dimensional conductive collagen gel scaffolds with conductive polymer nanofibres for tissue regeneration

Abstract

It has been established that nerves and skeletal muscles respond and communicate via electrical signals. In regenerative medicine, there is current emphasis on using conductive nanomaterials to enhance electrical conduction through tissue-engineered scaffolds to increase cell differentiation and tissue regeneration. We investigated the role of chemically synthesized polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer nanofibres for conductive gels. To mimic a naturally derived extracellular matrix for cell growth, type I collagen gels were reconstituted with conductive polymer nanofibres and cells. Cell viability and proliferation of PC-12 cells and human skeletal muscle cells on these three-dimensional conductive collagen gels were evaluated in vitro. PANI and PEDOT nanofibres were found to be cytocompatible with both cell types and the best results (i.e. cell growth and gel electrical conductivity) were obtained with a low concentration (0.5 wt%) of PANI. After 7 days of culture in the conductive gels, the densities of both cell types were similar and comparable to collagen positive controls. Moreover, PC-12 cells were found to differentiate in the conductive hydrogels without the addition of nerve growth factor or electrical stimulation better than collagen control. Importantly, electrical conductivity of the three-dimensional gel scaffolds increased by more than 400% compared with control. The increased conductivity and injectability of the cell-laden collagen gels to injury sites in order to create an electrically conductive extracellular matrix makes these biomaterials very conducive for the regeneration of tissues.

Three-dimensional co-culture of C2C12/PC12 cells improves skeletal muscle tissue formation and function

“…Electrical pulses from motor neurons are important for muscle development and differentiation in vivo . Many studies have attempted to mimic this electrical environment in vitro by the use of defined electrical pulses or improved electroconductive scaffolds (Donnelly et al , ; Ito et al , ; Sirivisoot et al , ). ES has been shown to improve myoblast differentiation into myotubes (Park et al , ).…”

Peripheral Nerve Regeneration Strategies: Electrically Stimulating Polymer Based Nerve Growth Conduits

“…A PANI-incorporated collagen matrix resulted in higher PC12 cell growth while a PEDOT-infused matrix resulted in greater neurogenic differentiation. 57 For instance, PC12 cells expressed significantly higher levels of MAP2 and β-tubulin III neurogenic marker expression on PEDOT incorporated gels and resulted in higher dendrite and axon outgrowth as compared to PANI gels without ES. Differences in cell growth and neurogenic differentiation may be due to the changes in gel properties as a result of blending with these fibers and potential cell-cell communication effects.…”

“…Collagen scaffolds containing PEDOT and PANI nanofibers were able to support PC12 cell growth and differentiation into nervelike cells in the absence of ES. 57 The incorporation of PANI or PEDOT was to render scaffolds electrically conductive. A PANI-incorporated collagen matrix resulted in higher PC12 cell growth while a PEDOT-infused matrix resulted in greater neurogenic differentiation.…”

Biomimetic scaffolds for regeneration of volumetric muscle loss in skeletal muscle injuries

“…Myoblasts seeded onto electrospun meshes with aligned nanofiber orientation generate highly aligned cultures that, when cultured in differentiation medium, readily fuse into aligned myotubes [109, 148]. Incorporating electrically conductive materials within synthetic scaffolding materials facilitated more efficient electrical stimulation of myoblast cultures, further improving myoblast differentiation compared to aligned fibers without stimulation [149–151]. Synthetic scaffolds can easily be fabricated with multiple growth factors incorporated into their bulk structure to facilitate the controlled release of these factors into a potential injury site [152].…”