The effects of injectable calcium silicate-based composites with the Chinese herb on an osteogenic accelerator in vitro

The synergistic effects of Xu Duan combined Sr-contained calcium silicate/poly-ε-caprolactone scaffolds for the promotion of osteogenesis marker expression and the induction of bone regeneration in osteoporosis

Osteoporosis and its related problems such as fractures are gradually becoming common due to an aging population. Current methods to treat osteoporosis include medical and surgical options such as bone implants. Recent developments in 3D printing and materials science technologies has allowed us to fabricate individualized scaffolds with desired properties. In this study, we mixed Xu Duan into strontium‑calcium silicate powder at 5% (XD5) and 10% (XD10) and fabricated 3D scaffolds with polycaprolactone. All scaffolds were assessed for its physical, mechanical, and biological properties to evaluated for its feasibility for bone tissue engineering in the osteoporosis model. Our results showed that such a scaffold could be fabricated using extrusion-based printing techniques and that addition of XD did not alter original structural properties of the SrCS. Furthermore, the XD5 and XD10 scaffolds were found to be non-toxic to cells and cells cultured on the scaffolds had significantly higher proliferation and secreted increased osteogenic-related proteins in in vitro studies as compared to the XD0 groups. Remarkably, the XD10 scaffolds could be used as substitutes for the critical-sized bone defect (7.0 mm diameter and 8.0 mm depth) in the osteoporotic rabbit model. The XD10 scaffolds can enhance bone ingrowth and accelerate new bone regeneration even in complex osteoporotic pathological environments. These results showed that such a Chinese medicine-contained scaffold had potential in osteoporosis bone tissue regeneration and could be considered as a promising tool for future clinical used applications.

Enhanced Capability of Bone Morphogenetic Protein 2-loaded Mesoporous Calcium Silicate Scaffolds to Induce Odontogenic Differentiation of Human Dental Pulp Cells

INTRODUCTION

Calcium silicate bioceramics have been broadly used as reparative or grafting materials with good bioactivity and biocompatibility in dental application. It has been shown that applying a mesoporous process to calcium silicate gives it great potential as a controlled drug delivery system.

METHODS

The aim of this study was to investigate a novel osteoinductive scaffold by loading bone morphogenetic protein 2 (BMP-2) to mesoporous calcium silicate (MesoCS) and fabricating it as 3-dimensional scaffolds using fused deposition modeling combined with polycaprolactone.

RESULTS

The MesoCS/BMP-2 scaffold showed similar patterns to that of a calcium silicate scaffold in releasing calcium and silicon ions in a simulated body fluid (SBF) immersion test for 7 days, but BMP-2 continued releasing from the MesoCS/BMP-2 scaffold significantly more than the CS scaffold from 48 hours to 7 days. Adhesion and proliferation of human dental pulp cells cultured on a MesoCS/BMP-2 scaffold were also more significant than scaffolds without BMP-2 or mesoporous as well as the results of the test on alkaline phosphatase activity.

CONCLUSIONS

The results support that the novel 3-dimensional-printed MesoCS scaffold performed well as BMP-2 delivery system and would be an ideal odontoinductive biomaterial in regenerative endodontics.

Surface Modification of Calcium Silicate via Mussel-Inspired Polydopamine and Effective Adsorption of Extracellular Matrix to Promote Osteogenesis Differentiation for Bone Tissue Engineering

Calcium silicate-based cement has garnered huge interest in recent years, due to its versatility and potential in mass fabrication of a variety of bioceramics. For this study, the main objective was to fabricate functionalized calcium silicate (CS) powder integrated with a simple bio-inspired surface modification using polydopamine (PDA), to regulate cellular behaviors such as cellular adhesion, and subsequently cell differentiation and proliferation. For this study, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques were used to analyze the chemical compositions and observe the surface characteristics of our PDA coated CS cements. Such modifications were found to enhance Wharton Jelly's mesenchymal stem cells (WJMSC) in various ways. Firstly, PDA-coated CS cements were found to significantly enhance cell adhesion with higher expressions of cell adhesion markers, such as focal adhesion kinase and integrins. This was further supported by morphology analysis of the cells. This enhanced cell adhesion, in turn, led to significantly higher secretion of extracellular matrix (ECM) proteins, such as collagen I and fibronectin, which directly promoted cell attachments and proliferation. In our osteogenesis assays, it was found that secretion and expression of osteogenesis related genes and proteins were significantly higher and were dependent on the PDA content. Therefore, these results demonstrated that such simple bio-inspired modification techniques of synthetic degradable CS cements can be applied as a future modification, to modify and convert inert surfaces of synthetic bone grafts to enhance and modulate the cell behaviors of WJMSCs. This in turn can be used as a potential alternative for further bioengineering research.

Calcium Silicate/Chitosan-Coated Electrospun Poly (Lactic Acid) Fibers for Bone Tissue Engineering

Electrospinning technology allows fabrication of nano- or microfibrous fibers with inorganic and organic matrix and it is widely applied in bone tissue engineering as it allows precise control over the shapes and structures of the fibers. Natural bone has an ordered composition of organic fibers with dispersion of inorganic apatite among them. In this study, poly (lactic acid) (PLA) mats were fabricated with electrospinning and coated with chitosan (CH)/calcium silicate (CS) mixer. The microstructure, chemical component, and contact angle of CS/CH-PLA composites were analyzed by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, various CS/CH-coated PLA mats increased the formation of hydroxyapatite on the specimens' surface when soaked in cell cultured medium. During culture, several biological characteristics of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA groups were promoted as compared to those on pure PLA mat. Increased secretion levels of Collagen I and fibronectin were observed in calcium silicate-powder content. Furthermore, with comparison to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs and their osteogenesis properties, which was characterized by osteogenic-related gene expression. These results clearly demonstrated that the biodegradable and electroactive CS/CH-PLA composite mats are an ideal and suitable candidate for bone tissue engineering.

Laser Sintered Magnesium-Calcium Silicate/Poly-ε-Caprolactone Scaffold for Bone Tissue Engineering

In this study, we manufacture and analyze bioactive magnesium-calcium silicate/poly-ε-caprolactone (Mg-CS/PCL) 3D scaffolds for bone tissue engineering. Mg-CS powder was incorporated into PCL, and we fabricated the 3D scaffolds using laser sintering technology. These scaffolds had high porosity and interconnected-design macropores and structures. As compared to pure PCL scaffolds without an Mg-CS powder, the hydrophilic properties and degradation rate are also improved. For scaffolds with more than 20% Mg-CS content, the specimens become completely covered by a dense bone-like apatite layer after soaking in simulated body fluid for 1 day. In vitro analyses were directed using human mesenchymal stem cells (hMSCs) on all scaffolds that were shown to be biocompatible and supported cell adhesion and proliferation. Increased focal adhesion kinase and promoted cell adhesion behavior were observed after an increase in Mg-CS content. In addition, the results indicate that the Mg-CS quantity in the composite is higher than 10%, and the quantity of cells and osteogenesis-related protein of hMSCs is stimulated by the Si ions released from the Mg-CS/PCL scaffolds when compared to PCL scaffolds. Our results proved that 3D Mg-CS/PCL scaffolds with such a specific ionic release and good degradability possessed the ability to promote osteogenetic differentiation of hMSCs, indicating that they might be promising biomaterials with potential for next-generation bone tissue engineering scaffolds.

Fabrication and characterization of polycaprolactone and tricalcium phosphate composites for tissue engineering applications

Background/purpose

β-Tricalcium phosphate (β-TCP) is an osteoconductive material which has been used for clinical purposes for several years, as is polycaprolactone (PCL), which has already been approved for a number of medical and drug delivery devices. In this study we have incorporated various concentrations of β-TCP into PCL with the aim of developing an injectable, mechanically strong, and biodegradable material which can be used for medical purposes without organic solvents.

Materials and methods

This study assesses the physical and chemical properties of this material, evaluates the in vitro bioactivity of the PCL/β-TCP composites, and analyzes cell proliferation and osteogenic differentiation when using human bone marrow mesenchymal stem cells (hBMSCs).

Results

The results show that weight losses of approximately 5.3%, 12.1%, 18.6%, and 25.2%, were observed for the TCP0, TCP10, TCP30, and TCP50 composites after immersion in simulated body fluid for 12 weeks, respectively, indicating significant differences (P < 0.05). In addition, PCL/β-TCP composites tend to have lower contact angles (47 ± 1.5° and 58 ± 1.7° for TCP50 and TCP30, respectively) than pure PCL (85 ± 1.3°), which are generally more hydrophilic. After 7 days, a significant (22% and 34%, respectively) increase (P < 0.05) in alkaline phosphatase level was measured for TCP30 and TCP50 in comparison with the pure PCL.

Conclusion

PCL/TCP is biocompatible with hBMSCs. It not only promotes proliferation of hBMSCs but also helps to differentiate reparative hard tissue. We suggest 50% (weight) PCL-containing β-TCP biocomposites as the best choice for hard tissue repair applications.

Hinokitiol-Loaded Mesoporous Calcium Silicate Nanoparticles Induce Apoptotic Cell Death through Regulation of the Function of MDR1 in Lung Adenocarcinoma Cells

Hinokitiol is a tropolone-related compound found in heartwood cupressaceous plants. Hinokitiol slows the growth of a variety of cancers through inhibition of cell proliferation. The low water solubility of hinokitiol leads to less bioavailability. This has been highlighted as a major limiting factor. In this study, mesoporous calcium silicate (MCS) nanoparticles, both pure and hinokitiol-loaded, were synthesized and their effects on A549 cells were analyzed. The results indicate that Hino-MCS nanoparticles induce apoptosis in higher concentration loads (>12.5 μg/mL) for A549 cells. Hino-MCS nanoparticles suppress gene and protein expression levels of multiple drug resistance protein 1 (MDR1). In addition, both the activity and the expression levels of caspase-3/-9 were measured in Hino-MCS nanoparticle-treated A549 cells. The Hino-MCS nanoparticles-triggered apoptosis was blocked by inhibitors of pan-caspase, caspase-3/-9, and antioxidant agents (N-acetylcysteine; NAC). The Hino-MCS nanoparticles enhance reactive oxygen species production and the protein expression levels of caspase-3/-9. Our data suggest that Hino-MCS nanoparticles trigger an intrinsic apoptotic pathway through regulating the function of MDR1 and the production of reactive oxygen species in A549 cells. Therefore, we believe that Hino-MCS nanoparticles may be efficacious in the treatment of drug-resistant human lung cancer in the future.

Enhanced adhesion and differentiation of human mesenchymal stem cell inside apatite-mineralized/poly(dopamine)-coated poly(ε-caprolactone) scaffolds by stereolithography

The purpose of this study is to develop PCL scaffolds using stereolithography technology and induced modifications using a poly dopamine (PDA)-coated/HA precipitate to stimulate human mesenchymal stem cells (hMSCs).

Preparation of the fast setting and degrading Ca-Si-Mg cement with both odontogenesis and angiogenesis differentiation of human periodontal ligament cells

Develop a fast setting and controllable degrading magnesium-calcium silicate cement (Mg-CS) by sol-gel, and establish a mechanism using Mg ions to stimulate human periodontal ligament cells (hPDLs) are two purposes of this study. We have used the diametral tensile strength measurement to obtain the mechanical strength and stability of Mg-CS cement; in addition, the cement degradation properties is realized by measuring the releasing amount of Si and Mg ions in the simulated body fluid. The other cell characteristics of hPDLs, such as proliferation, differentiation and mineralization were examined while hPDLs were cultured on specimen surfaces. This study found out the degradation rate of Mg-CS cements depends on the Mg content in CS. Regarding in vitro bioactivity; the CS cements were covered with abundant clusters of apatite spherulites after immersion of 24h, while less apatite spherulites were formatted on the Mg-rich cement surfaces. In addition, the authors also explored the effects of Mg ions on the odontogenesis and angiogenesis differentiation of hPDLs in comparison with CS cement. The proliferation, alkaline phosphatase, odontogenesis-related genes (DSPP and DMP-1), and angiogenesis-related protein (vWF and ang-1) secretion of hPDLs were significantly stimulated when the Mg content of the specimen was increased. The results in this study suggest that Mg-CS materials with this modified composition could stimulate hPDLs behavior and can be good bioceramics for bone substitutes and hard tissue regeneration applications as they stimulate odontogenesis/angiogenesis.