Chitosan-based Composites Research Articles

Single step synthesis of chitin/chitosan-based graphene oxide–ZnO hybrid composites for better electrical conductivity and optical properties

We synthesized two composites/hybrid composites with a graphene oxide (GO)/mixed GO–ZnO filler using either a chitin or a chitosan matrix. Fourier transform infrared spectroscopy analysis confirmed that chitin had been converted to chitosan during matrix fabrication because only chitosan, ZnO and GO were shown to be present in the composites/hybrid composites. Raman spectroscopy indicated the display of D and G bands at 1345cm−1 and 1584cm−1, respectively. UV absorption peaks appeared at 260–360nm and 201nm in both hybrid composites, which indicate a strong binding of ZnO within the chitosan–GO sheets. High resolution scanning electron microscopy and atomic force microscopy studies demonstrated that on a molecular scale ZnO was well dispersed in the hybrid composites. Impedance spectroscopy and a four-probe resistivity method were used for room temperature electrical conductivity measurements. The electrical conductivity of the chitin-based GO–ZnO hybrid composites was estimated to be ∼5.94×106S/cm and was greater than that of the chitosan-based GO–ZnO hybrid composite (∼4.13×106S/cm). The chitin-based GO–ZnO hybrid composite had a higher optical band gap (3.4eV) than the chitosan-based GO–ZnO hybrid composite (3.0eV). The current–voltage measurement showed that electrical sheets resistance of the chitosan-based composites decreased with formation of ZnO.

Osteogenic differentiation behaviors of mesenehymal stem cells on chitosan based network composites films

Objective To study the osteogenic differentiation capacity of mesenchymal stem cells（MSCs）on chitosan based biomimetic network composites films.Methods The chitosan-based biomimetic network composites films were prepared using chitosan,gelatin and pectin in certain ratio by biomimetic approach.The experiment was designed as follow：experimental group 1 （composites films＋routine medium）,control group 1 （routine medium）,experimental group 2（composites films＋osteogenic medium）,control group 2（osteogenic medium）.The growth and proliferation of MSCs were observed by inverted phase contrast microscope and scanning electronmicroscopy（SEM） and detected through methyl thiazolyl tetrazolium（MTT） assay.Alkaline phosphatase（ALP） activity was used to investigate the osteogenic differentiation capacity.The formation of mineral was determined by special staining and the energy dispersive X-ray apparatus （EDX）.Results MSCs could well adhere,grow and proliferate on the network composites films.The MTT assay demonstrated that there was no significant difference in cell viability between the experimental and control groups （P〉0.05）.SEM observation showed that MSCs grew assembly on the surface of the films secreted a large number of extracelluar matrix,and formed scattered nodules.The cells on the experimental group 1 showed statistically higher ALP activity level than those cells on the other groups （P〈0.01）.Moreover,the calcified nodules can be seen in the experimental groups by Alizarin red and Von Kossa staining.ALP staining showed blue-staining granules within the cytoplasm,and the deposition of Ca and P was detected on the films by SEM-EDX.Conclusion The novel chitosan-based biomimetic network composites films not only have good biocompatibility,but can also improve MSCs differentiation toward the osteogenic lineage. Key words: Chitosan; Network composites film; Mesenchymal stem cells; Viocompatibility; Osteogenic differentiation

EVALUATION OF CHITOSAN/CaSO4/PLATELET-RICH PLASMA MICROSPHERE COMPOSITES AS ALVEOLUS OSTEOGENESIS MATERIAL

Periodontal disease is the manifestation of serious bacteria infection that may extend to the gingival, periodontal ligaments, and alveolus bone. One commonly administrated treatment is the debridement therapy with the removal of infected area including the soft and hard lesion tissues. In some critical case, osteogenetic materials are being filled into the defective voids to improve the regeneration of slow-growing bony tissues. In attempt to improve bone regeneration, chitosan microsphere composites embedded with two osteogenesis beneficial ingredients, CaSO 4 and platelet-rich plasma (PRP), were fabricated by using a high voltage electrostatic field system. Three groups, chitosan/ CaSO 4 microspheres (Group A), chitosan/ CaSO 4 microspheres mixed with thrombin (Group B), and chitosan/ CaSO 4/PRP microspheres mixed with thrombin (Group C) were prepared. And, these chitosan-based composites were evaluated together with a control group in pig oral model for the bone regeneration study. The chitosan/ CaSO 4/PRP microsphere composites, exhibiting good sphericity, were in the range of 457.5 ± 59.3 μ m in diameter. Defects filled with Group B and Group C showed increases in new bone formation along with fibrous tissue regeneration as compared to that filled with Group A. The Masson's Trichrome stain observations suggested more abundant presence of fibrous collagen matrices around the defects after implanted with Group B over that of Group C microsphere composites. The preparation of chitosan/ CaSO 4-based microspheres was straight forward by using high voltage electrostatic field system. Furthermore, Chitosan/ CaSO 4-based microspheres with thrombin could be used successfully in regenerating new bone around the alveolus bone area.