Composition Of Outermost Layer Research Articles

Highly conductive and flexible silk fabric via electrostatic self assemble between reduced graphene oxide and polyaniline

In this paper, an electroconductive silk fabric is fabricated by electrostatic self assemble of reduced graphene oxide (RGO) and polyaniline (PANI) under acid aqueous solution lower the isoelectric point (pI) of silk. The RGO coated silk fabric (silk-RGO) is prepared by self assemble graphene oxide (GO) sheets on the surface of silk, then the GO reduced to RGO, and aniline (ANI) self-assembled on the surface of silk-RGO in situ polymerization of PANI. The results show that the electrical conductivity of silk is mainly influenced by the composition of outermost layer, the ANI and GO concentration, ANI dipping time also contribute to the electrical conductivity of silk. When PANI self-assembled on the outermost layer of silk-RGO, a blue-green, high conductive and flexible silk fabric with a lower electrical surface resistance of 0.330 K cm−1 was obtained. The SEM shows that RGO sheets formed a thin film on the surface of silk, and PANI deposited on the surface of silk with nanowires. The Raman and FTIR-ATR spectra of silk-PANI and silk-RGO-PANI are presented PANI characteristic peaks, and the thermostability of self-assembled samples enhanced.

Phosphoprotein/chitosan electrospun nanofibrous scaffold for biomineralization

In this study, negatively charged phosvitin (PV) and positively charged chitosan (CS) were alternately deposited on negatively charged cellulose mats via layer-by-layer (LBL) self-assembly technique. Morphologies of the LBL films coating mats were observed by scanning electron microscope (SEM). Afterwards, in vitro biomimetic mineralization was carried out through incubation of the fibrous mats in a simulated body fluid (SBF) solution for different time. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to characterize the morphology and structure of the deposited mineral phase on the scaffolds. In addition, the cell culture experiment demonstrated that the scaffolds with the LBL structured films were of good cell compatibility for MC3T3-E1 cells. Moreover, the cell proliferation was affected by the number of deposition layers and the composition of outer-most layer. Confocal laser scanning microscopy (CLSM) and SEM imaging revealed a good performance of cell adhesion and spreading of MC3T3-E1 cells on the surface of biocomposite scaffold. So CS/PV nanofibrous mats were satisfactory for the composite to be used in bioapplications.

Antibacterial multilayer films fabricated by LBL immobilizing lysozyme and HTCC on nanofibrous mats

Cellulose acetate nanofibrous mats were prepared by electrospunning technique. Positively charged and negatively charged composites were alternately deposited on negatively charged CA mats via layer-by-layer self-assembly technique. The morphology and inhibition rate of samples were investigated by regulating number of deposition bilayers and composition of outermost layer. Field emission scanning electron microscopy images indicated that the average diameter of fibers was increased with increasing the number of coating bilayers. Additionally, the catalytic activity of immobilized LY was measured and results showed “layer-by-layer alternative oscillation” phenomenon. The results of antibacterial assay indicated that (LY–HTCC/ALG)10.5 films coating had the best inhibitory effect.

Nanofibrous mats layer-by-layer assembled via electrospun cellulose acetate and electrosprayed chitosan for cell culture

Negatively charged cellulose acetate (CA) and positively charged chitosan (CS) were layer-by-layer (LBL) assembled together by the electrospinning–electrospraying hybrid technique via physical deposition and electrostatic force for the first time. The morphology of the mats indicated that all of them were of a good fiber shape and a three-dimension structure. The X-ray photoelectron spectroscopy results verified the existence of CS on the surface of the as-spun mats. The thermogravimetric analysis and differential scanning calorimetry results illustrated that the thermal properties of the mats were affected by their compositions. In addition, the cell culture experiment demonstrated that the scaffolds with the LBL structured polysaccharide films were of good cell compatibility and no cytotoxicity for the mouse lung fibroblasts cells. Moreover, the ability of cell adhesion and spreading was affected by the number of deposition layers and the composition of outermost layer.

Layer-by-layer structured polysaccharides film-coated cellulose nanofibrous mats for cell culture

For the first time, a novel fibrous polysaccharide scaffold for cell culture was fabricated by the combination of electrospinning and electrostatic layer-by-layer (LBL) self-assembly technique. Oppositely charged chitosan (CS) and alginate (ALG) in aqueous media were alternatively deposited onto the negatively charged cellulose nanofibrous mats which hydrolyzed from electrospun cellulose acetate mats. The morphology and biocompatibility of the resultant scaffolds were investigated by regulating the pH of dipping solutions, the number of deposition bilayers, and the composition of outermost layer. Field emission scanning electron microscopy images indicated that the scaffolds possessed the fibrous structure and the thickness of CS/ALG bilayer formed on fibers was estimated in the range of 8–15 nm. The X-ray photoelectron spectroscopy results verified the existence of nitrogen element of CS on the surface of LBL films. The cell culture experiments demonstrated that the scaffolds have good biocompatibility for Beas-2B human bronchial epithelial cells in vitro.