Effect of physicochemical properties of a cement based on silicocarnotite/calcium silicate on in vitro cell adhesion and in vivo cement degradation

In Vitro and In Vivo Biological Properties of Calcium Silicophosphate-Based Bone Grafts: Silicocarnotite and Nagelschmidtite

Accidents, trauma, bone defects, and oncological processes significantly impact patients' health and quality of life. While calcium phosphates and bioactive glasses are commonly used as bone fillers to facilitate bone regeneration in orthopedics and traumatology, they exhibit certain disadvantages compared to calcium silicophosphate phases. This study evaluates the in vitro cytocompatibility and in vivo osteogenic properties of two-third-generation ceramic phases: silicocarnotite (SC) and nagelschmidtite (Nagel). These phases were synthesized via a solid-state reaction and characterized using X-ray diffraction and scanning electron microscopy. In vitro behavior was assessed through bioactivity tests, cell viability, proliferation, and inflammatory profiles by detecting cytokines and reactive oxygen species. Osteogenic properties were evaluated by detecting bone-associated proteins in MG-G3, hFOB1.19, and MC3T3-E1 cell lines after 3, 7, and 14 days. 45S5 Bioactive glass (BG), hydroxyapatite (HAp), and osteogenic medium were employed as control standards for bone formation. SC and Nagel phases exhibited higher viability percentages as well as osteoconductive and osteoinductive behavior. Finally, SC and Nagel bone grafts were implanted in a Wistar rat model to assess their in vivo ability to induce bone formation, demonstrating complete osseointegration after 12 weeks. Histological evaluation revealed osteocytes forming osteons and the presence of blood vessels, particularly in rats implanted with Nagel. Given their favorable biological performance, SC and Nagel emerge as promising candidates for bone grafts in orthopedics, traumatology, and maxillofacial surgery.

Research Progress of Design Drugs and Composite Biomaterials in Bone Tissue Engineering

Bone, like most organs, has the ability to heal naturally and can be repaired slowly when it is slightly injured. However, in the case of bone defects caused by diseases or large shocks, surgical intervention and treatment of bone substitutes are needed, and drugs are actively matched to promote osteogenesis or prevent infection. Oral administration or injection for systemic therapy is a common way of administration in clinic, although it is not suitable for the long treatment cycle of bone tissue, and the drugs cannot exert the greatest effect or even produce toxic and side effects. In order to solve this problem, the structure or carrier simulating natural bone tissue is constructed to control the loading or release of the preparation with osteogenic potential, thus accelerating the repair of bone defect. Bioactive materials provide potential advantages for bone tissue regeneration, such as physical support, cell coverage and growth factors. In this review, we discuss the application of bone scaffolds with different structural characteristics made of polymers, ceramics and other composite materials in bone regeneration engineering and drug release, and look forward to its prospect.

Bioactive Calcium Phosphate-Based Composites for Bone Regeneration

Calcium phosphates (CaPs) are widely accepted biomaterials able to promote the regeneration of bone tissue. However, the regeneration of critical-sized bone defects has been considered challenging, and the development of bioceramics exhibiting enhanced bioactivity, bioresorbability and mechanical performance is highly demanded. In this respect, the tuning of their chemical composition, crystal size and morphology have been the matter of intense research in the last decades, including the preparation of composites. The development of effective bioceramic composite scaffolds relies on effective manufacturing techniques able to control the final multi-scale porosity of the devices, relevant to ensure osteointegration and bio-competent mechanical performance. In this context, the present work provides an overview about the reported strategies to develop and optimize bioceramics, while also highlighting future perspectives in the development of bioactive ceramic composites for bone tissue regeneration.

Bioinorganic supplementation of calcium phosphate-based bone substitutes to improve in vivo performance: a systematic review and meta-analysis of animal studies

Supplementation of CaP-based bone graft substitutes with bioinorganics such as strontium, zinc or silicon is an interesting approach to increase the biological performance in terms of bone regenerative potential of calcium phosphate (CaP)-based bone substitutes. However, the in vivo efficacy of this approach has not been systematically analyzed, yet. Consequently, we performed a systematic review using the available literature regarding the effect of bioinorganic supplementation in CaP-based biomaterials on new bone formation and material degradation in preclinical animal bone defect models and studied this effect quantitatively by performing a meta-analysis. Additional subgroup analyses were used to study the effect of different bioinorganics, animal model, or phase category of CaP-based biomaterial on bone formation or material degradation. Results show that bioinorganic supplementation increases new bone formation (standardized mean difference [SMD]: 1.43 SD, confidence interval [CI]: 1.13-1.73). Additional subgroup analysis showed that strontium, magnesium and silica significantly enhanced bone formation, while zinc did not have any effect. This effect of bioinorganic supplementation on new bone formation was stronger for DCPD or β-TCP and biphasic CaPs than for HA or α-TCP (p < 0.001). In general, material degradation was slightly hindered by bioinorganic supplementation (mean difference [MD]: 0.84%, CI: 0.01-1.66), with the exception of strontium that significantly enhanced degradation. Overall, bioinorganic supplementation represents an effective approach to enhance the biological performance of CaP-based bone substitutes.

Silicon-calcium phosphate ceramics and silicon-calcium phosphate cements: Substrates to customize the release of antibiotics according to the idiosyncrasies of the patient

Bone substitutes based on calcium phosphates can be classified in two major groups: ceramics and cements. Both are biomaterials with excellent biocompatibility that have been studied as local delivery systems for drugs. This study aims to evaluate drug-release kinetics in silicon beta-tricalcium phosphate ceramics (Si-β-TCP) and in silicon calcium phosphate cements (Si-CPCs). We want to investigate if the differences in composition and in structure of the Si-β-TCP and the Si-CPC may influence for drug loading and in its release kinetics from the biomaterial. The results obtained indicate that all drug-loaded materials were efficient to tailor drug release kinetics and inhibited the growth of Staphylococcus aureus. The cements prepared with high concentrations of silicon (80% Si-CPC) present zero-order release kinetics, independent of the drug concentration loaded. Si-β-TCP and Si-CPC offer a simple technology that could serve to personalize the delivery of bioactive molecules according to each patient's needs in the treatment of bone conditions, not only limited to prophylaxis, but also for the treatment of bone infection.

Calcium phosphate cements for bone engineering and their biological properties

Calcium phosphate cements (CPCs) are frequently used to repair bone defects. Since their discovery in the 1980s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability, bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs, including 3D printing, injectability, stem cell delivery, growth factor and drug delivery, and pre-vascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.

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.