Optimization of PVDF-TrFE Based Electro-Conductive Nanofibers: Morphology and In Vitro Response.

In this study, morphology and in vitro response of electroconductive composite nanofibers were explored for biomedical use. The composite nanofibers were prepared by blending the piezoelectric polymer poly(vinylidene fluoride-trifluorethylene) (PVDF-TrFE) and electroconductive materials with different physical and chemical properties such as copper oxide (CuO), poly(3-hexylthiophene) (P3HT), copper phthalocyanine (CuPc), and methylene blue (MB) resulting in unique combinations of electrical conductivity, biocompatibility, and other desirable properties. Morphological investigation via SEM analysis has remarked some differences in fiber size as a function of the electroconductive phase used, with a reduction of fiber diameters for the composite fibers of 12.43% for CuO, 32.87% for CuPc, 36.46% for P3HT, and 63% for MB. This effect is related to the peculiar electroconductive behavior of fibers: measurements of electrical properties showed the highest ability to transport charges of methylene blue, in accordance with the lowest fibers diameters, while P3HT poorly conducts in air but improves charge transfer during the fiber formation. In vitro assays showed a tunable response of fibers in terms of viability, underlining a preferential interaction of fibroblast cells to P3HT-loaded fibers that can be considered the most suitable for use in biomedical applications. These results provide valuable information for future studies to be addressed at optimizing the properties of composite nanofibers for potential applications in bioengineering and bioelectronics.

Field effect devices and sensors based on electrospun polymer assisted tin oxide nanoribbons.

Electrospinning is presented as a facile method of preparing relatively long tin oxide (SnO2) nanofibers that are robust and stable in air. Upon heat treatment, the fibers collapse into a ribbon-like structure with surfaces that are not smooth, rather, are marked with several interconnected pathways. These nanoribbons were electrically characterized in a field effect transistor configuration in vacuum, with and without ultra violet (UV) light exposure. The resultant variable resistor device exhibits n-type behavior having an on/off ratio of approximately 6000. The devices show a direct response to UV with faster response times upon exposure to longer wavelength light. In the presence of UV, the device conductance and mobility increases, reaching a value approximately 2 cm2/-s for the 364 nm UV light source, comparable to amorphous Si.