Novel barium-doped-baghdadite incorporated PHBV-PCL composite fibrous scaffolds for bone tissue engineering

Bioceramic/polymer composites have dragged a lot of attention for treating hard tissue damage in recent years. In this study, we synthesized barium-doped baghdadite (Ba-BAG), as a novel bioceramic, and later developed fibrous composite poly (hydroxybutyrate) co (hydroxyvalerate)- polycaprolactone (PHBV-PCL) scaffolds containing different amounts of baghdadite (BAG) and Ba-BAG, intended to be used in bone regeneration. Our results demonstrated that BAG and Ba-doped BAG powders were synthesized successfully using the sol-gel method and their microstructural, physicochemical, and cytotoxical properties results were evaluated. In the following, PHBV/PCL composite scaffolds containing different amounts of BAG and Ba-BAG (1, 3, and 5 wt%) were produced by the wet electrospinning method. The porosity of scaffolds decreased from 78% to 72% in Ba-BAG-incorporated PHBV/PCL scaffolds. The compressive strength of the scaffolds was between 4.69 and 9.28 kPa, which was increased to their maximum values in the scaffolds with Ba-BAG. The presence of BAG and Ba-BAG in the polymer scaffolds resulted in increasing bioactivity, and it was introduced as a suitable way to control the degradation rate of scaffolds. The presence of the BAG component was a major reason for higher cell proliferation in reinforced PHBV/PCL polymeric scaffolds, while Ba existence played its influential role in the higher osteogenic activity of cells on Ba-BAG incorporated PHBV/PCL scaffolds. Thus, the incorporation of Ba-BAG bioceramic materials into the structure of polymeric PHBV/PCL scaffolds promoted their various properties, and allow these scaffolds to be used as promising candidates in bone tissue engineering applications.

In Vitro Biocompatibility of the Novel Ceramic Composite Baghdadite for Defect Augmentation in Revision Total Hip Arthroplasty

Biological augmentation of bony defects in weight-bearing areas of both the acetabulum and the femur remains challenging. The calcium-silicate-based ceramic Baghdadite is a very interesting material to be used in the field of revision total hip arthroplasty for the treatment of bony defects in weight-bearing and non-weight-bearing areas alike. The aim of this study was to investigate the biocompatibility of Baghdadite utilizing an osteoblast-like, human osteosarcoma cell line (MG-63) and the human monocytic leukemia-derived cell line (THP-1). THP-1-derived macrophages and MG-63 were indirectly exposed to Baghdadite for 7 days using a transwell system. Viability was assessed with MTT assay and pH analysis. To investigate proliferation rate, both cell lines were labelled using CFSE and flow cytometrically analyzed. ELISA was used to measure the secretion of IL-1ß, IL-6 and TNFα. The investigation of viability, while showing a slight difference in optical density for the MTT assays in MG-63 cells, did not present a meaningful difference between groups for both cell lines. The comparison of pH and the proportion of living cells between groups did not present with a significant difference for both THP-1 and MG-63. Baghdadite did not have a relevant impact on the proliferation rate of the investigated cell lines. Mean fluorescence intensity was calculated between groups with no significant difference. Baghdadite exerted a proinflammatory effect, which could be seen in an upregulated production of TNFα in macrophages. Production of IL-1ß and IL-6 was not statistically significant, but the IL-6 ELISA showed a trend to an upregulated production as well. A similar effect on MG-63 was not observed. No relevant cytotoxicity of Baghdadite ceramics was encountered. Baghdadite ceramics exhibit a proinflammatory potential by significantly increasing the secretion of TNFα in THP-1-derived macrophages. Whether this proinflammatory potential results in a clinically relevant effect on osteointegration is unclear and requires further investigation. Baghdadite ceramics provide an interesting alternative to conventional bone substitutes and should be further investigated in a biomechanical and in vivo setting.

3D porous bioceramic based boron-doped hydroxyapatite/baghdadite composite scaffolds for bone tissue engineering

Making composite scaffolds is one of the well-known methods to improve the properties of scaffolds used in bone tissue engineering. In this study, novel ceramic-based 3D porous composite scaffolds were successfully prepared using boron-doped hydroxyapatite, as the primary component, and baghdadite, as the secondary component. The effects of making composites on the properties of boron-doped hydroxyapatite-based scaffolds were investigated in terms of physicochemical, mechanical, and biological properties. The incorporation of baghdadite contributed to making more porous scaffolds (over 40%) with larger surface area and micropore volumes. The produced composite scaffolds almost solved the low degradation problem of boron-doped hydroxyapatite through the exhibition of higher biodegradation rates, which matched the degradation rate appropriate for the gradual transfer of loads from implants to newly formed bone tissues. Besides higher bioactivity, enhanced cell proliferation, as well as higher osteogenic differentiation (in scaffolds with baghdadite weight greater than 10%), were observed in composite scaffolds due to both physical and chemical modifications that occurred in composite scaffolds. Although our composite scaffolds were slightly weaker than boron-doped hydroxyapatite, their compressive strengths were higher than almost all composite scaffolds made by baghdadite incorporation in the literature. In fact, boron-doped hydroxyapatite provided a base for baghdadite to show mechanical strength suitable for cancellous bone defect treatments. Eventually, our novel composite scaffolds converged the advantages of both components to satisfy the various requirements needed for bone tissue engineering applications and take us one step forward on the road to fabricating an ideal scaffold.

Baghdadite coating formed by hybrid water-stabilized plasma spray for bioceramic applications: Mechanical and biological evaluations

This work studies the mechanical and biological properties of Baghdadite (BAG, Ca₃ZrSi₂O₉) coating manufactured on Ti6Al4V substrates by hybrid water-stabilized plasma spray (WSP-H). Hydroxyapatite (HAp, Ca₁₀(PO₄)₆(OH)₂) coating was produced by gas-stabilized atmospheric plasma spray and used as a reference material. Upon spraying, the BAG coating exhibited lower crystallinity than the HAp coating. Mechanical testing demonstrated superior properties of the BAG coating: its higher hardness, elastic modulus as well as a better resistance to scratch and wear. In the cell viability study, the BAG coating presented better human osteoblast attachment and proliferation on the coating surface after three days and seven days compared to the HAp counterpart. Furthermore, the gene expression study of human osteoblasts indicated that the BAG coating surface showed higher expression levels of osteogenic genes than those on the HAp coating. Overall, this study indicates that enhanced mechanical and bioactive properties can be achieved for the BAG coating compared to the benchmark HAp coating. It is therefore concluded here that the BAG coating is a potential candidate for coating orthopedic implants.

In vitro evaluation of diopside/baghdadite bioceramic scaffolds modified by polycaprolactone fumarate polymer coating

Porous Si-based ceramic scaffolds are widely attracted in biomedical tissue engineering application. Despite the attractive properties of these materials, their weak mechanical properties and high degradability in vitro and in vivo environment can limit their application as biomedical devises. Applying a thin layer of polymer on the surface of porous scaffolds can improve the mechanical properties and control the degradation rate. In this study, we produced new modified scaffolds with polymers coating in order to improved mechanical and biological properties of Si-based ceramics scaffolds. The results showed that applying 6 wt% PCLF polymer on the surface of Bagh-15 wt%Dio scaffolds delayed apatite formation compared to unmodified scaffolds. On the other hand, in the modified scaffolds, apatite formation was observed. The degradation rate of unmodified scaffolds was decreased around 82% after 28 days soaking in PBS solution. Based on the MTT assay and SEM micrographs, the BMS cells were spread and attached well on the surface of the scaffolds, which indicated a good biocompatibility. The results showed that these scaffolds have the potential to be used as a temporary substrate for bone tissue engineering application.

Baghdadite nanoparticle-coated poly l-lactic acid (PLLA) ceramics scaffold improved osteogenic differentiation of adipose tissue-derived mesenchymal stem cells

Bone repair has been a new approach in regenerative medicine especially by application of stem cells. Discovering a suitable combination of scaffolds to stimulate osteogenesis is one of the major concerns in this issue. Porous polymeric scaffolds such as poly l-lactic acid (PLLA) have been attracted a lot of attention because of their biodegradability. In the present study, we have been coated Baghdadite on the plasma-treated surface of PLLA and evaluated osteogenic potential of mesenchymal stem cells (MSCs). Adipose tissue-derived mesenchymal stem cells (AD-MSCs) were cultured on PLLA and PLLA-Baghdadite scaffolds, and cell properties were characterized by MTT assay, scanning electron microscope, and FTIR analysis. Then, osteogenic differentiation potential of AD-MSCs has been investigated, such as alkaline phosphatase (ALP) activity, calcium mineral deposition, and the expression of bone-related genes (RUNX2, ALP, and OCN). The results have been indicated that calcium content and ALP activity of cells cultured on PLLA-Baghdadite nanofibers were higher than that of tissue culture polystyrenes (TCPs). Gene expression analysis showed that PLLA-Baghdadite had effectively induced osteogenesis-related genes. Taken together, these results suggest that porous nanofiber scaffolds which coated with Baghdadite can enhance osteogenic differentiation of AD-MSC, and PLLA-Baghdadite can be used as a new biodegradable scaffold for bone regeneration. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1284-1293, 2019.