Preparation of self-assembly scaffolds via electrostatic attachment of calcium alginate microspheres / 中国组织工程研究

ABSTRACT

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 21. The positively charged chitosan microspheres could attach to the negatively calcium alginate microspheres to form a self-assembly scaffold.