Evaluation of mechanical property and bioactivity of nano-bioglass 45S5 scaffold coated with poly-3-hydroxybutyrate

Abstract

One of the major challenges facing researchers of tissue engineering is scaffold design with desirable physical and mechanical properties for growth and proliferation of cells and tissue formation. In this research, firstly, nano-bioglass powder with grain sizes of 55-56 nm was prepared by melting method of industrial raw materials at 1,400 °C. Then the porous ceramic scaffold of bioglass with 30, 40 and 50 wt% was prepared by using the polyurethane sponge replication method. The scaffolds were coated with poly-3-hydroxybutyrate (P3HB) for 30 s and 1 min in order to increase the scaffold's mechanical properties. XRD, XRF, SEM, FE-SEM and FT-IR were used for phase and component studies, morphology, particle size and determination of functional groups, respectively. XRD and XRF results showed that the type of the produced bioglass was 45S5. The results of XRD and FT-IR showed that the best temperature to produce bioglass scaffold was 600 °C, in which Na2Ca2Si3O9 crystal is obtained. By coating the scaffolds with P3HB, a composite scaffold with optimal porosity of 80-87% in 200-600 μm and compression strength of 0.1-0.53 MPa was obtained. According to the results of compressive strength and porosity tests, the best kind of scaffold was produced with 30 wt% of bioglass immersed for 1 min in P3HB. To evaluate the bioactivity of the scaffold, the SBF solution was used. The selected scaffold (30 wt% bioglass/6 wt% P3HB) was maintained for up to 4 weeks in this solution at an incubation temperature of 37 °C. The XRD, SEM EDXA and AAS tests were indicative of hydroxyapatite formation on the surface of bioactive scaffold. This scaffold has some potential to use in bone tissue engineering.

Evaluation of physical and mechanical properties of B-tri-calcium phosphate/poly-3-hydroxybutyrate nanocomposite scaffold for bone tissue engineering application

“…Porosity and density measurements Liquid displacement was used to calculate the porosity and density of the sca olds. Sca old density provides information about the size, distribution, and permeability of pores and the presence of structural defects in sintered ceramic frameworks [13].…”

“…Machining and gripping the specimen is a major problem in the mechanical characterization of porous ceramic structures; conventional methods of mechanical characterization, such as tensile, biaxial, and impact tests, are usually inapplicable to biomaterial with porous frameworks [13]. Compression impact tests for porous bone and n -TCP specimens with cellular structure are instead applied [13,40].…”

“…Compression impact tests for porous bone and n -TCP specimens with cellular structure are instead applied [13,40]. Compressive strength and compressive modulus tests for n -TCP sca olds with and without P3HB were measured using a compression impact tester (SANTAM-Eng.…”

“…In other words, tissue function restoration needs a template, a sca old, which will play the role of extracellular matrix in order to allow cells to attach, migrate, and duplicate tissue ingrowth until the new tissue is fully regenerated [11,12]. Bone tissue has a great potential for being restored to other body tissues [13]. Inherently, natural bone tissue is a composite of a collagenous hydrogel matrix consisting of about 33-43% apatite minerals, 32-44% organics, and 15-25% water on a volumetric basis [14,15], which is accountable for the remarkable strength and partial elasticity in bone tissue [16].…”

“…However, since CaPO 4 has a ceramic nature, they are brittle; therefore, biomedical applications of bare CaPO 4 sca olds for bone tissue reconstruction have been largely limited by their poor mechanical properties such as compression strength, compression module, and toughness [32]. Hence, CaPO 4 sca olds have been modi ed by introducing ductile polymer as a reinforcing phase in order to improve the mechanical properties and decrease their brittleness [13]. For example, collagen coated BCP ceramics were studied and the biocompatibility towards osteoblasts was found to increase upon coating with collagen [33].…”