BACKGROUND: Microspheric injectable scaffold has a perspective in cartilage tissue engineering; however, it is still limited by in vivo hard forming and microsphere transmigration.OBJECTIVE: To investigate the feasibility of self-assembly scaffolds by attaching negatively charged calcium alginate microspheres and positively charged chitosan microspheres by electrostatic force. METHODS: The calcium alginate and chitosan microspheres were prepared by emulsion-internal gelation and spray drying technique, respectively. The characterizations of the microspheres were determined by means of scanning electron microscopy, optical microscopy and zeta potential analysis methods. Self-assembly scaffolds were fabricated by mixing the aqueous suspensions of the microspheres with oppositely charged surfaces. The phenomenon of electrostatic attachment was characterized by optical microscopy and scanning electron microscopy, and the elastic compress modulus of the scaffolds was also investigated.RESULTS AND CONCLUSION: The average diameter of the calcium alginate microspheres was 52.5 μm, and the chitosan one was 4.1 μm, respectively. The zeta-potential of the calcium alginate microspheres was 23.5 mv, and the chitosan one was +9.8 mv, respectively. The microspheres were spherical and smooth. The small size chitosan microspheres could attach to the surface of the calcium alginate microspheres and anchor the calcium alginate microspheres together. The elastic compress modulus increased with the increase of solid content of the microspheres, but decreased with the increase of the ionic strength. The elastic compress modulus increased firstly and then decreased with the increase of the mass ratio of m (CHI):m (ALG), and it showed the highest elastic compress modulus when m (CHI):m (ALG) was 2:1. The positively charged chitosan microspheres could attach to the negatively calcium alginate microspheres to form a self-assembly scaffold.

BACKGROUND:Silk fibroin as natural biological macromolecules has good biocompatibility, but it is difficult to make the three-dimensional scaffold with uniform structure because of its higher crystalization performance and bigger brittleness. OBJECTIVE:To improve the crystalization of silk fibroin through the addition of chitosan, and to get three-dimensional tissue engineering scaffolds with better mechanical strength. METHODS: CaCl2/CH3CH2OH/H2 RESULTS AND CONCLUSION:The introduction of chitosan could improve the properties of scaffolds. The porosity of the composite scaffold with lower porosity was more uniform and orderly with higher content of O ternary solution was used to dissolve silkworm cocoon to extract silk fibroin and form solution. Silk fibroin solution and chitosan solution were mixed according to different mixing ratios of 2:1, 1:1, 1:2, respectively, and then porous silk protein/chitosan scaffolds were prepared by freeze-drying method and treated by methanol. Scaffold morphology was observed by scanning electron microscopy, the chemical structure and crystaline state of the scaffolds were characterized through infrared spectrum and X-ray diffraction test, respectively. Also, the porosity and water uptake were tested and periodic cycle compression mechanical properties under the water environment were determined. chitosan. When the mixture rate of chitosan and silk fibroin was 1:2, the water uptake rate was the highest in the composite scaffolds, and also higher than that of the silk fibroin scaffold but lower than that of the chitosan scaffold. With the increase of silk fibroin, the composite scaffolds had better elasticity and stronger ability to maintain the shape.

A novel cornea tissue scaffold material was prepared with N-vinly pyrrolidome (NVP) and a biodegradable crosslinking agent by radical polymerization, using azoisobutyronitrile (AIBN) as initiator. Water absorption test and contact angle measure were conducted, and the degradation process of material was investigated. The biocompatibility evaluation was carried out by implantation of material in the rabbits, and by cell culture. The water absorption was over 104%, the contact angle was lower than 41degrees, and the degradation speed in vitro kept steady. The results of implantation in the rabbits showed that the material was almost degraded 3 months later and lots of collagen and cornea stroma cells appeared in it,but there was no inflammation around it. The result of epithelial cells culture showed that the cells conglutinated on the material, but no remarkable cytotoxicity was noted.
Animals ; Biocompatible Materials ; chemistry ; Cornea ; cytology ; Epithelium, Corneal ; cytology ; Materials Testing ; Nitriles ; chemistry ; Prostheses and Implants ; Pyrrolidinones ; chemistry ; Rabbits ; Tissue Engineering