Ultrathin electrospun PANI nanofibers for neuronal tissue engineering

N-(4-aminophenyl)aniline oxidative polymerization is optimized to produce polyaniline (PANI) free from carcinogenic and/or polluting coproducts. The resulting polymer is electrospun using polymethyl methacrylate (PMMA) as the supporting polymer, with different weight ratios (1:0, 4:1, 3:1, 2:1, 1:1, and 0.5:1 w/w PANI/PMMA). By rinsing with a selective solvent, PMMA is removed while maintaining the fibrous morphology. Ultrathin (65 ± 14 nm) and defect-free PANI nanofiber mats are obtained for the blend containing a high relative content of PANI (2:1 w/w, namely F2:1). Two different solvents are tested to remove PMMA, namely acetone and isopropanol, the former giving better results, as highlighted by infrared spectroscopy (FTIR). X-ray diffraction (XRD) demonstrates that the electrospun PANI is amorphous. The thin fiber mats are robust and sterilization both by autoclave and UV irradiation can be carried out. UV irradiation is preferred since no modification of the fibrous morphology is detectable. In vitro biocompatibility of the electrospun F2:1 fibers has been evaluated with SH-SY5Y neuronal-like cells. Indirect cytocompatibility tests show that no cytotoxic leachable is released by the electrospun mats at both short and longer times, while direct cytocompatibility investigations indicate that only F2:1 fibers washed in isopropanol do not reduce cell proliferation rate with respect to controls on tissue culture plates. Globally, these results suggest that the proposed electrospun nanostructures are promising materials for neuronal tissue engineering.