Conductive electrospun polyurethane-polyaniline scaffolds coated with poly(vinyl alcohol)-GPTMS under oxygen plasma surface modification

Abstract

Polyurethane is an important synthetic polymer which considered promising for bone tissue engineering. Besides, presence of conductive polymer such as could play a crucial role in efficient reconstruction of injured tissue. In the present study, the polyurethane-polyaniline scaffolds were fabricated by electrospinning technology. The electrospun fibers were modified by oxygen plasma treatment technique for immobilization of polyvinyl alcohol and 3-Glycidoxypropyl-trimethoxysilane. Eventually, the prepared constructs were characterized using proper analysis including morphology and roughness observation, chemical characterization, water-scaffolds interaction and biomineralization potential, cellular adhesion and proliferation, and finally osteogenic expression. According to microscopy results, bead-free, uniform, and nano-sized fibers were obtained; after coating, the surface was covered homogeneously with polyvinyl alcohol and 3-glycidoxypropyl-trimethoxysilane. The electrospun scaffolds showed highly porous structures, and their large surface-to-volume ratio made them suitable for tissue engineering applications. The degree of roughness and the mean height were increased from 96.59 nm to 144.4 and 267–429 nm, respectively, after the oxygen plasma surface treatment. Additionally, the modified fibers showed improved hydrophilicity and swelling capacity compared with pure polyurethane-polyaniline constructs. The contact angle of the polyurethane-polyaniline, oxygen plasma modified polyurethane-polyaniline, oxygen plasma modified polyurethane-polyaniline coated with polyvinyl alcohol, and oxygen plasma modified polyurethane-polyaniline coated with polyvinyl alcohol-3-glycidoxypropyl-trimethoxysilane scaffolds was 116.33°, 65.64°, 60.17°, and 62.50°, respectively. Although the addition of 3-glycidoxypropyl-trimethoxysilane led to a slight reduction in absorption potential, it could induce mineralization of hydroxyapatite-like layers which was proved by microscopy images and crystalline peaks in X-ray diffraction spectra. Ameliorating the cell attachment and the viability of a higher number of the cells after the surface treatment and coating process confirmed the biocompatible nature of the scaffolds. Also, in the alkaline phosphatase activity, all groups showed significant (p < 0.0001) increases compared with the control group. Expression of alkaline phosphatase proved the initial potential of the constructs for further pre-clinical and clinical analyses in order to reconstruct the injured bones.