Strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate, and function. For this purpose, hybrid biomaterials based on smart combinations of biodegradable polymers and bioactive glasses (BGs) are of particular interest, since they exhibit tailored physical, biological, and mechanical properties, as well as predictable degradation behavior. In this study, hybrid biomaterials with different organic-inorganic ratios were successfully synthesized via a sol-gel process. Poly(ε-caprolactone) (PCL) and tertiary bioactive glass (BG) with a glass composition of 70 mol % SiO(2), 26 mol % CaO, and 4 mol % of P(2)O(5) were used as the polymer and inorganic phases, respectively. The polymer chains were successfully introduced into the inorganic sol while the networks were formed. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) were used to investigate the presence of different chemical groups, structural crystallinity, thermal property, elemental composition, and homogeneity of the synthesized hybrid biomaterials. Identification of chemical groups and the presence of molecular interaction by hydrogen bonding between the organic and inorganic phases was confirmed by FTIR. The XRD patterns showed that all PCL/BG hybrids (up to 60% polymer content) were amorphous. The TGA study revealed that the PCL/BG hybrid biomaterials were thermally stable, and good agreement was observed between the experimental and theoretical organic-inorganic ratios. The SEM/EDX results also revealed a homogeneous elemental distribution and demonstrated the successful incorporation of all the elements in the hybrid system. Finally, these synthesized hybrid biomaterials were successfully electrospun into 3D scaffolds. The resultant fibers have potential use as scaffolds for bone regeneration.

Strategies for bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix and act as templates onto which cells attach, multiply, migrate and function. Of particular interest are nanocomposites and organic-inorganic (O/I) hybrid biomaterials based on selective combinations of biodegradable polymers and bioactive inorganic materials. In this paper, we review the current state of bioactive and biodegradable nanocomposite and O/I hybrid biomaterials and their applications in bone regeneration. We focus specifically on nanocomposites based on nano-sized hydroxyapatite (HA) and bioactive glass (BG) fillers in combination with biodegradable polyesters and their hybrid counterparts. Topics include 3D scaffold design, materials that are widely used in bone regeneration, and recent trends in next generation biomaterials. We conclude with a perspective on the future application of nanocomposites and O/I hybrid biomaterials for regeneration of bone.

The behavior of cells responsible for bone formation, osseointegration, and bone bonding in vivo are governed by both the surface chemistry and topography of scaffold matrices. Bone-like apatite coatings represent a promising method to improve the osteoconductivity and bonding of synthetic scaffold materials to mineralized tissues for regenerative procedures in orthopedics and dentistry. Polycaprolactone (PCL) films were coated with calcium phosphates (CaP) by incubation in simulated body fluid (SBF). We investigated the effect of SBF ion concentration and soaking time on the surface properties of the resulting apatite coatings. CaP coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and energy dispersive X-ray spectrometry (EDX). Young's modulus (E(s)) was determined by nanoindentation, and surface roughness was assessed by atomic force microscopy (AFM) and mechanical stylus profilometry. CaP such as carbonate-substituted apatite were deposited onto PCL films. SEM and AFM images of the apatite coatings revealed an increase in topographical complexity and surface roughness with increasing ion concentration of SBF solutions. Young's moduli (E(s)) of various CaP coatings were not significantly different, regardless of the CaP phase or surface roughness. Thus, SBF with high ion concentrations may be used to coat synthetic polymers with CaP layers of different surface topography and roughness to improve the osteoconductivity and bone-bonding ability of the scaffold.

Investigation of novel biomaterials for bone regeneration is based on the development of scaffolds that exhibit bone-bonding ability, biocompatibility, and sufficient mechanical strength. In this study, using novel poly (ε-caprolactone)/bioactive glass (PCL/BG) hybrids with different organic/inorganic ratios, the effects of BG contents on the in vitro bone-like hydroxyapatite (HA) formation, mechanical properties, and biocompatibility were investigated. Rapid precipitation of HA on the PCL/BG hybrid surfaces were observed after incubating in simulated body fluid (SBF) for only 6 h, as confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and inductively coupled plasma atomic emission spectroscopy (ICPS). The ICPS elemental analysis results were further analyzed in terms of the Ca(2+) and PO4(3-) which were consumed to form the apatite layer. The results revealed that the rate and total amount of HA deposition decreased with an increase in PCL content. The compressive modulus and strength of the PCL/BG hybrids increased with the decrease in PCL content. The highest values were achieved at the lowest PCL content (10 wt %) and were around, 90 MPa and 1.4 GPa, respectively. To evaluate the cytotoxicity of PCL/BG bioactive hybrids, MC3T3-E1 osteoblast-like cells were cultured for up to 72 h. Our data indicated that whereas initial cell attachment was marginally lower than the control tissue culture poly styrene (TCPS) surface, the hybrid materials promoted cell growth in a time-dependent manner. Cell viability within the different PCL/BG hybrid samples appeared to be influenced by compositional differences whereby higher PCL contents correlated with slight reduction in cell viability. Taken together, this study adds important new information to our knowledge on hydroxyapatite formation, mechanical properties, and cytotoxic effects of PCL/BG hybrids prepared by the sol-gel process using a tertiary glass composition and may have considerable potential for bone tissue regeneration applications.

No abstract