Introduction: In tissue engineering, tissue regeneration occurs through a designed scaffold filled with molecular signals and cells. The 45S5 bioglass (BG) contains 45% SiO2, 24.5% Na2O, 24.4% CaO and 6% P2O5 in weight which is a suitable material for use in tissue engineering as a scaffold due to their high bioactivity, non-toxicity, and excellent biocompatibility. In spite of their good properties, the low mechanical properties, especially in the load-bearing limited their applications. Ceramic reinforcements and polymer coatings are the most effective methods used to enhance the mechanical properties of BG. Titania (TiO2) as a biocompatible bioceramic is used to reinforce the BG scaffold but researches show that this is not enough. Poly (3-hydroxybutyrate) (PHB), as a family of polyhydroxyalkanoates, are biocompatible with good mechanical properties but they are hydrophobic. The addition of chitosan (Cs) as a hydrophilic polymer solves this problem because the proper cell behavior depended on hydrophilic surfaces. So PHB/Cs were chosen for coating the nBG/nTiO2 composite scaffolds in this study for use in tissue engineering applications.
Methods: The nBG-nTiO2 base scaffold with interconnected pores was fabricated by foam replication method (FRM). After the nBG/nTiO2 composite scaffolds were made, the polymer solution by the dip-coating method used for coating the scaffolds. The FTIR, XRD, SEM, Porosity measurement, mechanical and contact angle analysis were performed on the scaffolds.
Results: The results obtained from SEM showed that scaffolds with and without coating have high porosity and well-interconnected pore structure, and the polymer coating caused a significant increase in the mechanical properties from 0.01 Mpa to 0.19 Mpa. This coating also had a significant effect on the reduction of the contact angle, which resulted in better hydrophilicity due to the presence of Cs.
Conclusion: 3D composite scaffolds of nBG/nTiO2 were fabricated by FRM. PHB and PHB/Cs were covered on scaffolds by the dip-coating method. The polymer coating did not affect the interconnectivity of the pore structure while it had a significant effect on the mechanical properties of scaffolds. Also, the presence of Cs in the coated scaffolds had a positive effect on reducing the contact angle. Hence, the composite scaffold obtained from the results of this investigation can be considered a candidate for bone tissue engineering applications.
Keywords: Bioglass, Bone tissue engineering, Chitosan, Poly(3-hydroxybutyrate), Titania