Ultrathin electrospun PANI nanofibers for neuronal tissue engineering

Abstract

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 6 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 F 2:1 ). 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 F 2:1 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 F 2:1 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.

Conductive Bicomponent Fibers Containing Polyaniline Produced via Side-by-Side Electrospinning

“…In the literature, electrospun PANI fibers had a wide range of conductivity, depending on many factors, such as the selection of matrix polymer, the volumetric ratio of the matrix polymer to doped PANI, and fiber morphologies. For instance, the conductivity of PANI and PEO blends was in the magnitude of 10 1 S/cm to 10 −4 S/cm in some studies [20,22], and the conductivity of PANI and PVP mats was lower than 10 −8 S/cm reported by others [23,26,29,30,31,33,35,36,37,38,39,40,41,42]. It is also noteworthy that the conductivity testing method is a non-negligible factor.…”

“…Electrospinning was the most common spinning method to prepare PANI fibers due to its versatility for comprehensive purposes and applications. Poly(ethylene oxide) (PEO), poly(lactic acid), polyvinylpyrrolidone, poly(methyl methacrylate), poly(vinylidene fluoride), and polystyrene have been frequently reported for blending with PANI [20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42]. Among these, PEO is the most used matrix polymer [20,21,22,23,43,44,45,46] because of its good spinnability and availability in wide range of molecular weight along with the nontoxic, fully biodegradable, and biocompatible traits [47].…”

Photocatalytic and Oxidative Synthetic Pathways for Highly Efficient PANI-TiO2 Nanocomposites as Organic and Inorganic Pollutant Sorbents

“…It should be underlined that the reaction cannot proceed further without the addition of H 2 O 2 , as clearly shown by the change in color from violet to dark green, characteristic of polyaniline, upon H 2 O 2 addition. Oxygen peroxide is known to act as both a radical source initiating PANI synthesis, as well as an oxidant supporting the polymer growth [72]. In PANI_ref synthesis, previous studies have shown that H 2 O 2 dissociation in the presence of a catalyst can produce radical species (HO•) able to promote the formation of initiators (aniline dimer radicals) [72].…”

“…Oxygen peroxide is known to act as both a radical source initiating PANI synthesis, as well as an oxidant supporting the polymer growth [72]. In PANI_ref synthesis, previous studies have shown that H 2 O 2 dissociation in the presence of a catalyst can produce radical species (HO•) able to promote the formation of initiators (aniline dimer radicals) [72]. These are crucial for the first part of the reaction, which follows a radical mechanism.…”

Sterilization of PAN/Gelatine Nanofibrous Mats for Cell Growth

“…Unexpectedly, possibilities to sterilize nanofi brous mats before the addition of cells and their potential infl uences on cell growth are only scarcely mentioned in the scientifi c literature. Castagna et al performed autoclaving and UV irradiation to sterilize polyaniline nanofi brous mats [25]. Arnal-Pastor et al used immersion in 70% ethanol for 3 hours, which necessitated careful rinsing with sterile phosphatebuff ered saline to remove ethanol residues, making this method very time-consuming [26].…”