ABSTRACT
Poly(3-hydroxybutyrate) (P(3HB)) foams exhibiting highly interconnected porosity (85% porosity) were prepared using a unique combination of solvent casting and particulate leaching techniques by employing commercially available sugar cubes as porogen. Bioactive glass (BG) particles of 45S5 Bioglass grade were introduced in the scaffold microstructure, both in micrometer ((m-BG), <5 microm) and nanometer ((n-BG), 30 nm) sizes. The in vitro bioactivity of the P(3HB)/BG foams was confirmed within 10 days of immersion in simulated body fluid and the foams showed high level of protein adsorption. The foams interconnected porous microstructure proved to be suitable for MG-63 osteoblast cell attachment and proliferation. The foams implanted in rats as subcutaneous implants resulted in a non-toxic and foreign body response after one week of implantation. In addition to showing bioactivity and biocompatibility, the P(3HB)/BG composite foams also exhibited bactericidal properties, which was tested on the growth of Staphylococcus aureus. An attempt was made at developing multifunctional scaffolds by incorporating, in addition to BG, selected concentrations of Vitamin E or/and carbon nanotubes. P(3HB) scaffolds with multifunctionalities (viz. bactericidal, bioactive, electrically conductive, antioxidative behaviour) were thus produced, which paves the way for next generation of advanced scaffolds for bone tissue engineering.
Subject(s)
Hydroxybutyrates/pharmacology , Polyesters/pharmacology , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Adsorption/drug effects , Animals , Bacterial Adhesion/drug effects , Biocompatible Materials/pharmacology , Cell Line , Cell Proliferation/drug effects , Ceramics/pharmacology , Colony Count, Microbial , Culture Media , Humans , Hydrogen-Ion Concentration/drug effects , Implants, Experimental , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Nanotubes, Carbon , Porosity/drug effects , Rats , Rats, Sprague-Dawley , Staphylococcus aureus/cytology , Staphylococcus aureus/drug effects , Staphylococcus aureus/growth & development , Staphylococcus aureus/ultrastructure , Thermogravimetry , Vitamin E/pharmacologyABSTRACT
This study investigated the possibility of incorporating alpha-tocopherol (vitamin E) into poly(3hydroxybutyrate) (P(3HB))/Bioglass composites, which are being developed for bone tissue engineering matrices. P(3HB) films with 20 wt% Bioglass and 10 wt% vitamin E were prepared using the solvent casting technique. Addition of vitamin E significantly improved the hydrophilicity of the composites along with increasing the total protein adsorption. The presence of protein adsorbed on the composite surface was further confirmed using X-ray photoelectron spectroscopy analysis. Preliminary cell culture studies using MG-63 human osteoblasts showed that the addition of vitamin E in the P(3HB)/20 wt% Bioglass films significantly increased cell proliferation. The results achieved in this study confirmed the possibility of incorporating vitamin E as a suitable additive in P(3HB)/Bioglass composites to engineer the surface of the composites by promoting higher protein adsorption and increasing the hydrophilicity.
Subject(s)
Antioxidants/chemistry , Ceramics/chemistry , Hydroxybutyrates/chemistry , Polyesters/chemistry , Vitamin E/chemistry , Adsorption , Animals , Antioxidants/pharmacology , Blood Proteins/chemistry , Cattle , Cell Adhesion/drug effects , Cell Growth Processes/drug effects , Cell Line, Tumor , Ceramics/pharmacology , Humans , Hydroxybutyrates/pharmacology , Microscopy, Electron, Scanning , Osteoblasts/cytology , Osteoblasts/drug effects , Polyesters/pharmacology , Surface Properties , Tissue Engineering/methods , Vitamin E/pharmacologyABSTRACT
This study compares the effects of introducing micro (m-BG) and nanoscale (n-BG) bioactive glass particles on the various properties (thermal, mechanical and microstructural) of poly(3hydroxybutyrate) (P(3HB))/bioactive glass composite systems. P(3HB)/bioactive glass composite films with three different concentrations of m-BG and n-BG (10, 20 and 30 wt%, respectively) were prepared by a solvent casting technique. The addition of n-BG particles had a significant stiffening effect on the composites, modulus when compared with m-BG. However, there were no significant differences in the thermal properties of the composites due to the addition of n-BG and m-BG particles. The systematic addition of n-BG particles induced a nanostructured topography on the surface of the composites, which was not visible by SEM in m-BG composites. This surface effect induced by n-BG particles considerably improved the total protein adsorption on the n-BG composites compared to the unfilled polymer and the m-BG composites. A short term in vitro degradation (30 days) study in simulated body fluid (SBF) showed a high level of bioactivity as well as higher water absorption for the P(3HB)/n-BG composites. Furthermore, a cell proliferation study using MG-63 cells demonstrated the good biocompatibility of both types of P(3HB)/bioactive glass composite systems. The results of this investigation confirm that the addition of nanosized bioactive glass particles had a more significant effect on the mechanical and structural properties of a composite system in comparison with microparticles, as well as enhancing protein adsorption, two desirable effects for the application of the composites in tissue engineering.
