Controlling the bone regeneration properties of bioactive glass: Effect of particle shape and size

GelMA hydrogels reinforced by PCL@GelMA nanofibers and bioactive glass induce bone regeneration in critical size cranial defects

BACKGROUND

The process of bone healing is complex and involves the participation of osteogenic stem cells, extracellular matrix, and angiogenesis. The advancement of bone regeneration materials provides a promising opportunity to tackle bone defects. This study introduces a composite hydrogel that can be injected and cured using UV light.

RESULTS

Hydrogels comprise bioactive glass (BG) and PCL@GelMA coaxial nanofibers. The addition of BG and PCL@GelMA coaxial nanofibers improves the hydrogel's mechanical capabilities (353.22 ± 36.13 kPa) and stability while decreasing its swelling (258.78 ± 17.56%) and hydration (72.07 ± 1.44%) characteristics. This hydrogel composite demonstrates exceptional biocompatibility and angiogenesis, enhances osteogenic development in bone marrow mesenchymal stem cells (BMSCs), and dramatically increases the expression of critical osteogenic markers such as ALP, RUNX2, and OPN. The composite hydrogel significantly improves bone regeneration (25.08 ± 1.08%) in non-healing calvaria defects and promotes the increased expression of both osteogenic marker (OPN) and angiogenic marker (CD31) in vivo. The expression of OPN and CD31 in the composite hydrogel was up to 5 and 1.87 times higher than that of the control group at 12 weeks.

CONCLUSION

We successfully prepared a novel injectable composite hydrogel, and the design of the composite hydrogels shows significant potential for enhancing biocompatibility, angiogenesis, and improving osteogenic and angiogenic marker expression, and has a beneficial effect on producing an optimal microenvironment that promotes bone repair.

Enhancing the Biological Properties of Organic-Inorganic Hybrid Calcium Silicate Cements: An In Vitro Study

(1) Background: This study aimed to enhance the biological properties of hydraulic calcium silicate cements (HCSCs) by incorporating organic and inorganic components, specifically elastin-like polypeptides (ELPs) and bioactive glass (BAG). We focused on the effects of these composites on the viability, migration, and osteogenic differentiation of human periodontal ligament fibroblasts (hPDLFs). (2) Methods: Proroot MTA was supplemented with 1-5 wt% 63S BAG and 10 wt% ELP. The experimental groups contained various combinations of HSCS with ELP and BAG. Cell viability was assessed using an MTT assay, cell migration was evaluated using wound healing and transwell assays, and osteogenic activity was determined through Alizarin Red S staining and a gene expression analysis of osteogenic markers (ALP, RUNX-2, OCN, and Col1A2). (3) Results: The combination of ELP and BAG significantly enhanced the viability of hPDLFs with an optimal BAG concentration of 1-4%. Cell migration assays demonstrated faster migration rates in groups with 2-4% BAG and ELP incorporation. Osteogenic activity was the highest with 2-3% BAG incorporation with ELP, as evidenced by intense Alizarin Red S staining and the upregulation of osteogenic differentiation markers. (4) Conclusions: The incorporation of ELP (organic) and BAG (inorganic) into HCSC significantly enhances the viability, migration, and osteogenic differentiation of hPDLFs. These findings suggest that composite HCSC might support healing in destructed bone lesions in endodontics.

Histomorphometric and Micro-CT Evaluation of Cerabone and Bio-Oss in Maxillary Sinus Lifting: A Randomized Clinical Trial

Background and Objectives: The loss of teeth in the posterior maxillary region often leads to significant alveolar bone resorption and maxillary sinus pneumatization, complicating dental implant placement. Maxillary sinus grafting, typically using autogenous bone, is a common solution. However, autogenous bone grafts require additional surgical procedures, leading to increased morbidity. This study aims to compare the efficacy of two xenografts, Bio-Oss and Cerabone, in promoting new bone formation in maxillary sinus grafting through histomorphometric analysis and micro-computed tomography (micro-CT). Materials and Methods: A total of 22 maxillary sinuses (12 right and 10 left) were grafted, with 12 using Cerabone and 10 using Bio-Oss. Six months post-grafting, biopsies were collected for histomorphometric analysis to measure new bone formation, connective tissue, and residual biomaterial. Additionally, micro-CT analysis was performed to assess bone volume fraction, trabecular thickness, number, and separation. Results: Histomorphometric analysis showed that the Cerabone group had a higher average new bone formation (25.94% ± 10.55) compared to the Bio-Oss group (17.29% ± 4.61), with a statistically significant difference (p = 0.02). Micro-CT analysis revealed that the bone volume fraction in the Cerabone group was significantly higher compared to the Bio-Oss group, with significant differences in trabecular thickness (p = 0.02) but not in trabecular number or separation. Conclusions: The study demonstrates that both xenografts are effective in promoting new bone formation in maxillary sinus grafting. However, Cerabone showed superior performance in terms of new bone formation and bone volume fraction, suggesting it may be a more effective option for maxillary sinus augmentation procedures.

Biodegradable implant of magnesium/polylactic acid composite with enhanced antibacterial and anti-inflammatory properties

Addressing fracture-related infections (FRI) and impaired bone healing remains a significant challenge in orthopedics and stomatology. Researchers aim to address this issue by utilizing biodegradable biomaterials, such as magnesium/poly lactic acid (Mg/PLA) composites, to offer antibacterial properties during the degradation of biodegradable implants. Existing Mg/PLA composites often lack sufficient Mg content, hindering their ability to achieve the desired antibacterial effect. Additionally, research on the anti-inflammatory effects of these composites during late-stage degradation is limited. To strengthen mechanical properties, bolster antibacterial efficacy, and enhance anti-inflammatory capabilities during degradation, we incorporated elevated Mg content into PLA to yield Mg/PLA composites. These composites underwent in vitro degradation studies, cellular assays, bacterial tests, and simulation of the PLA degradation microenvironment. 20 wt% and 40 wt% Mg/PLA composites displayed significant antibacterial properties, with three composites exhibiting notable anti-inflammatory effects. In contrast, elevated Mg content detrimentally impacted mechanical properties. The findings suggest that Mg/PLA composites hold promise in augmenting antibacterial and anti-inflammatory attributes within polymers, potentially serving as temporary regenerative materials for treating bone tissue defects complicated by infections.

Characterization of an advanced bone graft material with a nanocrystalline hydroxycarbanoapatite surface and dual phase composition

The bone formation response of ceramic bone graft materials can be improved by modifying the material's surface and composition. A unique dual-phase ceramic bone graft material with a nanocrystalline, hydroxycarbanoapatite (HCA) surface and a calcium carbonate core (TrelCor®-Biogennix, Irvine, CA) was characterized through a variety of analytical methods. Scanning electron microscopy (SEM) of the TrelCor surface (magnification 100-100,000X) clearly demonstrated a nanosized crystalline structure covering the entire surface. The surface morphology showed a hierarchical structure that included micron-sized spherulites fully covered by plate-like nanocrystals (<60 nm in thickness). Chemical and physical characterization of the material using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy Energy Dispersive X-ray Spectroscopy (SEM-EDX) showed a surface composed of HCA. Analysis of fractured samples confirmed the dual-phase composition with the presence of a calcium carbonate core and HCA surface. An in vitro bioactivity study was conducted to evaluate whether TrelCor would form a bioactive layer when immersed in simulated body fluid. This response was compared to a known bioactive material (45S5 bioactive glass - Bioglass). Following 14-days of immersion, surface and cross-sectional analysis via SEM-EDX showed that the TrelCor material elicited a bioactive response with the formation of a bioactive layer that was qualitatively thicker than the layer that formed on Bioglass. An in vivo sheep muscle pouch model was also conducted to evaluate the ability of the material to stimulate an ectopic, cellular bone formation response. Results were compared against Bioglass and a first-generation calcium phosphate ceramic that lacked a nanocrystalline surface. Histology and histomorphometric analysis (HMA) confirmed that the TrelCor nanocrystalline HCA surface stimulated a bone formation response in muscle (avg. 11% bone area) that was significantly greater than Bioglass (3%) and the smooth surface calcium phosphate ceramic (0%).

Development and Characterization of Gadolinium and Copper Reinforced Bioactive Glass: An In Vitro Study

INTRODUCTION

Bioactive glass, an innovative alloplastic material utilizing a matrix of silica particles combined with calcium and phosphorus, has been widely employed for the regeneration of bony defects due to its bone-forming capabilities and biocompatibility. Nevertheless, it comes with several drawbacks, including a slow degradation rate, low mechanical strength, and susceptibility to fractures. To address these issues, the present research was done to develop and characterize a novel bioactive glass incorporating gadolinium (Gd) and copper (Cu).

METHODS

The bioactive glass doped with Gd and Cu were synthesized and subjected to characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), and attenuated total reflectance-infrared (ATR-IR) analysis.

RESULTS

The bioactive glass, enriched with Gd and Cu, underwent analysis using ATR-IR spectroscopy, XRD, and SEM. ATR-IR revealed characteristic silicate bands, while SEM indicated the presence of particles larger than 4 μm. XRD analysis identified the formation of Na2Ca4(PO4)2SiO4 (Silicorhenatite), Na2Ca2Si3O9 (Combeite), and wollastonite (calcium inosilicate mineral; CaSiO3). The crystalline nature of these compounds contributed to the favorable mechanical properties of the bioactive glass.

CONCLUSION

In summary, the creation of the innovative Gd-Cu-incorporated bioactive glass demonstrates favorable mechanical characteristics, suggesting significant promise for augmenting bone regeneration.

Fabrication and Characterization of an Innovative Silver- and Gadolinium-Doped Bioglass for Bone Regeneration

Background Periodontal regeneration aims for the three-dimensional reconstruction of bone defects, and over the years, bone grafts with or without barrier membranes have provided us with promising results. Particulate bone grafts can be classified according to the source of procurement as autografts, allografts, xenografts, and alloplasts. Bioglass, an innovative alloplast that uses silica particles as a matrix incorporated with calcium and phosphorus, has been extensively used as a propitious material for bone regeneration owing to its inherent osteogenic ability and biocompatibility but presents with various disadvantages such as slow degradation rate, low mechanical strength, and fracture resistance. A novel silver (Ag)-gadolinium (Gd)-doped bioglass was fabricated to improve the mechanical properties, biocompatibility, and osteogenic ability when compared with bioglass (control). Materials and methods The Ag- and Gd-doped bioglass network was prepared and assessed for the morphological and structural properties by scanning electron microscopy (SEM) analysis, X-ray diffraction (XRD), and attenuated total reflectance (ATR)-infrared (IR). The cytotoxicity of Gd and Ag-doped bioglass was assessed using the MG63 cell line through the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assay at various concentrations and the absorbance of the solution was measured at 570 nm using a microplate reader. The osteogenic ability of the material was assessed by alkaline phosphatase activity and collagen estimation. Results ATR-IR spectroscopy, SEM, and XRD were used to examine the bioglass network doped with Gd and Ag. ATR-IR exhibited classic silicate bands, whereas SEM indicated particles bigger than 5 μm. XRD analysis revealed the production of Na2Ca2Si3O9, Na2Ca4(PO4)2SiO4, and wollastonite. The excellent crystallinity of Na2Ca2Si3O9 provided the bioglass network with good mechanical characteristics. The Gd-Ag-bioglass did not exhibit any toxicity towards the living cells at increasing concentrations from 12.5 µg to 100 µg. The alkaline phosphatase activity was increased by 10% and the collagen estimation remained consistent with bioglass (control). Conclusion In conclusion, the fabrication of the novel Gd-Ag-doped bioglass shows good cytocompatibility and osteogenic ability and shows great potential to enhance bone regeneration.

The synergetic effect of hierarchical pores and micro-nano bioactive glass on promoting osteogenesis and angiogenesis in vitro

Hierarchical pores are important structural components of the bone tissue and are closely related to angiogenesis, nutrient transport, and metabolism involved in the repair of a bone defect. Here, we fabricated a composite scaffold having a hierarchical structure, based on micro-nano bioactive glass (MNBG) incorporated into poly (lactic-co-glycolic acid) (PLGA), and with camphene as a pore-forming agent for bone repair. The results showed that camphene formed abundant micropores in the walls of large pores, resulting in hierarchical pore structures ranging from a few microns to a hundred microns. Moreover, there was 2-3 folds increased in compressive modulus and the scaffolds showed a stable degradation rate and a higher degree of apatite crystallization than ordinary porous scaffolds. The results of in vitro studies showed that, when compared to ordinary porous scaffolds, PLGA-MNBG scaffolds with multi-holes could better promote the proliferation of bone marrow mesenchymal stem cells (BMSCs) and the expression of angiogenic marker (CD31) of human umbilical vein endothelial cells (HUVECs).

[Research progress on biocomposites based on bioactive glass]

Bioactive glass (BG) has been widely used in the preparation of artificial bone scaffolds due to its excellent biological properties and non-cytotoxicity, which can promote bone and soft tissue regeneration. However, due to the brittleness, poor mechanical strength, easy agglomeration and uncontrollable structure of glass material, its application in various fields is limited. In this regard, most current researches mainly focus on mixing BG with organic or inorganic materials by freeze-drying method, sol-gel method, etc., to improve its mechanical properties and brittleness, so as to increase its clinical application and expand its application field. This review introduces the combination of BG with natural organic materials, metallic materials and non-metallic materials, and demonstrates the latest technology and future prospects of BG composite materials through the development of scaffolds, injectable fillers, membranes, hydrogels and coatings. The previous studies show that the addition of BG improves the mechanical properties, biological activity and regeneration potential of the composites, and broadens the application of BG in the field of bone tissue engineering. By reviewing the recent BG researches on bone regeneration, the research potential of new materials is demonstrated, in order to provide a reference for future related research.

Evaluation of biocomposite putty with strontium and zinc co-doped 45S5 bioactive glass and sodium hyaluronate

The application of powder or granule formed bioactive glasses in the defect area with the help of a liquid carrier to fill the defects is a subject of interest and is still open to development. In this study, it was aimed to prepare biocomposites of bioactive glasses incorporating different co-dopants with a carrier biopolymer and to create a fluidic material (Sr and Zn co-doped 45S5 bioactive glasses‑sodium hyaluronate). All biocomposite samples were pseudoplastic fluid type, which may be suitable for defect filling and had excellent bioactivity behaviors confirmed by FTIR, SEM-EDS and XRD. Biocomposites with Sr and Zn co-doped bioactive glass had higher bioactivity considering the crystallinity of hydroxyapatite formations compared to biocomposite with undoped bioactive glasses. Biocomposites with high bioactive glass content had hydroxyapatite formations with higher crystallinity compared to biocomposites with low bioactive glass. Furthermore, all biocomposite samples showed non-cytotoxic effect on the L929 cells up to a certain concentration. However, biocomposites with undoped bioactive glass showed cytotoxic effects at lower concentrations compared to biocomposites with co-doped bioactive glass. Thus, biocomposite putties utilizing Sr and Zn co-doped bioactive glasses may be advantageous for orthopedic applications due to their specified rheological, bioactivity, and biocompatibility properties.

Synthesis of Hierarchically Porous Bioactive Glass and Its Mineralization Activity

Mesoporous bioactive glass is a promising biomaterial for bone tissue engineering due to its good biocompatibility and bioactivity. In this work, we synthesized a hierarchically porous bioactive glass (HPBG) using polyelectrolyte-surfactant mesomorphous complex as template. Through the interaction with silicate oligomers, calcium and phosphorus sources were successfully introduced into the synthesis of hierarchically porous silica, and HPBG with ordered mesoporous and nanoporous structures was obtained. The morphology, pore structure and particle size of HPBG can be controlled by adding block copolymer as co-template or adjusting the synthesis parameters. The ability to induce hydroxyapatite deposition in simulated body fluids (SBF) demonstrated the good in vitro bioactivity of HPBG. Overall, this work provides a general method for the synthesis of hierarchically porous bioactive glasses.

A Degradable and Osteogenic Mg-Based MAO-MT-PLGA Drug/Ion Delivery System for Treating an Osteoporotic Fracture

Osteoporotic fractures are a very common bone disease that is difficult to completely cure. A large number of people worldwide suffer from pain caused by osteoporotic fractures every year, which can even cause disability and death. The compromised skeletal strength, lower density, trabecular microstructure, and bone-forming ability caused by osteoporotic fractures make them difficult to treat relative to normal fractures. An ideal scheme for osteoporotic fractures is to select internal fixation materials with matched mechanical and biological properties and carry anti-osteoporosis drugs on the plant to achieve bio-fixation and improve the condition of osteoporosis simultaneously. We designed a Mg-based MAO-MT-PLGA drug/ion delivery system (DDS) compatible with bone-like mechanical properties, degradation properties, and drug therapy. In this research, we evaluated the degradation behavior of Mg-based MAO-MT-PLGA DDS using immersion tests and electrochemical tests aided by SEM, EDS, XPS, XRD, and FT-IR. The DDS showed better corrosion resistance over Mg alloy and could release more Mg2+ due to the degradation of PLGA. According to cell viability and cell adhesion, the DDS showed better osteogenic characteristics over control group I (Mg alloy) and control group II (Mg-based MAO alloy), especially in the cells co-cultured with the leaching solution for 72 h, in which the DDS group increased to about 15% cell viability compared with group I (p < 0.05). The mRNA relative expressions, including ALP, collagen I, OCN, OPG, and Runx-2, as well as extracellular matrix calcium deposits of the DDS, are 1.5~2 times over control group I and control group II (p < 0.05), demonstrating a better ability to promote bone formation and inhibit bone resorption. After the DDS was implanted into the castrated rat model for one month, the trabeculae in the treatment group were significantly denser and stronger than those in the control group, with a difference of about 1.5 times in bone volume fraction, bone density, and the number of trabeculae, as well as the magnesium content in the bone tissue (p < 0.05). The above results demonstrated that the Mg-based MAO-MT-PLGA drug/ion delivery system is a potential treatment for osteoporotic fractures.