Para-substituted sulfonic acid-doped protonated emeraldine salt nanobuds: a potent neural interface targeting PC12 cell interactions and promotes neuronal cell differentiation.

Structural parameters, such as metal-like semiconductor and electrochemical properties of functionalized polyaniline, hold great potential especially for the development of the cell-substrate interface due to its ion/electron transfer ability. We report the one-step synthesis of sulfonic acid-doped polyaniline nanobuds (s-PANINbs) with controlled shape/size under various oxidation potentials. The different oxidation states of s-PANINbs are used to investigate the cell-specific platform for the induction of neuronal networks in PC12 cells, including the growth, proliferation, and differentiation of cells. The unique structure of one-dimensional (1-D) s-PANINbs enhances its intrinsic conductive properties, and facilitates the dispersibility and electrochemical activity via covalent bonding with dopants. The protonated emeraldine salt nanobuds of s-PANINbs synthesized at 0.18 V anodic potential demonstrated low resistivity (∼81.18 mΩ) and charge transfer resistance (∼3253 Ω). The most biologically compatible protonated emeraldine salt was used in vitro to induce PC12 cells associated with neurite outgrowth, contributing to the electrophysiology of neuronal cells under an external electrical stimulation. The western blotting analysis and qRT-PCR results show that ß-III Tubulin, synapsin I, and TREK-1 are highly expressed in PC12 cells, confirming their successful differentiation into neural-specific cells. Our approach demonstrates the promising role of the self-standing framework based on the s-PANINbs of the protonated emeraldine salt in peripheral nerve repair for the future in vivo cell-interface.

A conducting neural interface of polyurethane/silk-functionalized multiwall carbon nanotubes with enhanced mechanical strength for neuroregeneration.

A fibrous scaffold, fully assimilating polyurethane (PU) and silk fibroin associated with functionalized multi-walled carbon nanotubes (fMWCNTs) was developed by electrospinning technique. Herein, we engineered the PU/Silk fibroin-fMWCNTs-based biomaterial that shows great promise as electrospun scaffolds for neuronal growth and differentiation, because of its unique mechanical properties, hydrophilicity, and biodegradability, with outstanding biocompatibility in nerve tissue engineering. The morphology and structural properties of the scaffolds were studied using various techniques. In particular, the presence of fMWCNTs enhances the electrical conductivity and plausible absorption of sufficient extracellular matrix (ECM). The in vitro tests revealed that the aligned scaffolds (PU/Silk-fMWCNTs) significantly stimulated the growth and proliferation of Schwann cells (S42), together with the differentiation and spontaneous neurite outgrowth of rat pheochromocytoma (PC12) cells that were particularly guided along the axis of fiber alignment. The conductive PU/Silk-fMWCNTs scaffold significantly improves neural expression in vitro with successful axonal regrowth, which was confirmed by immunocytochemistry and qRT-PCR analysis. Inspired by the comprehensive experimental results, the fMWCNTs-based scaffold affords new insight into nerve-guided conduit design from both conductive and protein rich standpoints, and opens a new perspective on peripheral nerve restoration in preclinical applications.