Preparation And Functional Properities Of Natural Polysaccharide-based Modified Cellulose Nanofibrous Mats

In the past decades, nanofibers have gained a great deal of attention due to the unique properties including ultrafine fiber, high surface area per unit mass and remarkable high porosity, and have been widely applied in the field of drug delivery and tissue engineering et al. In this paper, the structure, biocompatibility and bioactivity of natural polysaccharide (chitosan (CS) and its derivative, Alginate sodium (ALG) and cellulose)-based nanofibrous composite mats were studied. OREC, as a kind of organically modified layered silicates which has similar structure to the montmorillonite, was introduced successfully into the LBL structured nanofibrous mats to be investigated. The quaternized chitosan (HTCC)/Organic rectorite (OREC) nanofibrous composite mats were prepared via electrospinning, solution polymer-layered silicate intercalation and layer-by-layer self-assembly techniques, then the topological structure and physicochemical property of prepared mats were characterized by systematic methods, and the LBL modified mats were further applied to the in vitro cell culture experiments to investigate their bioactivity including biocompatibility and antitumor effect, aiming at providing theoretical basis for developing novel functional biomaterials in Clinical cancer treatment. Main conclusions are summarized as follows:1. The HTCC-OREC/ALG modified nanofibrous mats with various coating bilayers and the component of outmost layer were successfully fabricated, the topological structure and physicochemical property of prepared mats were characterized by FT-IR、Zeta-potential、FE-SEM、XRD and XPS. Fiber diameter distribution results from Field Emission Scanning Electron Microscopy (FE-SEM) images showed that the average fiber diameter of (HTCC-OREC/ALG)n films coating obviously increased from 433 nm to 608 nm. Moreover, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results further confirmed the interaction between HTCC and OREC and their successful immobilization on cellulose template.2. CCL-13 cells and SMMC-7721 were selected to perform the cell culture experiments, the MTT assay, SEM combined with IFM analysis were applied to study the bioactivity including the cytotoxicity, biocompatibility and antitumor activity of prepared samples, the MTT assay indicated that the prepared nanofibrous mats exhibited strong inhibitory activity against human hepatocellular carcinoma cells (SMMC-7721) but a little cytotoxic effect on human Chang liver (CCL-13) cells. Furthermore, the experimental results from FE-SEM and Inverted Fluorescence Microscope of SMMC-7721 cells cultured on LBL structured nanofibrous mats demonstrated the significant antitumor activity of prepared samples against SMMC-7721 cells by inhibiting their growth, spreading and proliferation.To solve the problem caused by the oxidative stress induced by reactive oxygen radicals (ROS) released by hydrogen peroxide (H2O2), catalase, known as a kind of oxidation-reduction enzymes, this study also immobilized catalase on electrospun cellulose nanofibrous mats via LBL technique, and it was proved that the prepared mats reduced the oxidative impairment of HUVEs caused by H2O2, the protective effect of enzyme-immobilized nanofibrous mats to the cells exposed to H2O2 could offer scientific evidence for the mitigating ROS-induced impairment and the application in medical field. Main conclusions are summarized as follows:1. The immobilization of enzyme was accomplished by electrospinning and LBL methods, and the FE-SEM> XPS were used to characterized the morphology and structure of the prepared nanofibrous mats, it was confirmed that the CS and CAT were both successfully deposited on the surface of the nanofibers, moreover, the bound enzyme and enzyme activity on the mats were quantificationally determined by UV-vis.2. MTT assay, LDH release assay were performed to investigate the cytotoxicity of H2O2 against HUVEs and the The damage level of the cell membrane, and the combination with FCM, SEM and TEM further illustrate the mechanism of apoptosis induced by H2O2, more importantly, the significantly improvement effect of CAT-immobilized nanofibrous mats for hydrogen peroxide induced cell damage was confirmed.