Regeneration Of New Bone Research Articles

Aspirin-Loaded Anti-Inflammatory ZnO-SiO2 Aerogel Scaffolds for Bone Regeneration.

The increasing aging of the population has elevated bone defects to a significant threat to human life and health. Aerogel, a biomimetic material similar to an extracellular matrix (ECM), is considered an effective material for the treatment of bone defects. However, most aerogel scaffolds suffer from immune rejection and poor anti-inflammatory properties and are not well suited for human bone growth. In this study, we used electrospinning to prepare flexible ZnO-SiO2 nanofibers with different zinc concentrations and further assembled them into three-dimensional composite aerogel scaffolds. The prepared scaffolds exhibited an ordered pore structure, and chitosan (CS) was utilized as a cross-linking agent with aspirin (ASA). Interestingly, the 1%ZnO-SiO2/CS@ASA scaffolds not only exhibited good biocompatibility, bioactivity, anti-inflammation, and better mechanical properties but also significantly promoted vascularization and osteoblast differentiation in vitro. In the mouse cranial defect model, the BV/TV data showed a higher osteogenesis rate in the 1%ZnO-SiO2/CS group (10.94 ± 0.68%) and the 1%ZnO-SiO2/CS@ASA group (22.76 ± 1.83%), compared with the control group (5.59 ± 2.08%), and in vivo studies confirmed the ability of 1%ZnO-SiO2/CS@ASA to promote in situ regeneration of new bone. This may be attributed to the fact that Si4+, Zn2+, and ASA released from 1%ZnO-SiO2/CS@ASA scaffolds can promote angiogenesis and bone formation by stimulating the interaction between endothelial cells (ECs) and BMSCs, as well as inducing macrophage differentiation to the M2 type and downregulating the expression of pro-inflammatory factor (TNF-α) to modulate local inflammatory response. These exciting results and evidence suggest that it provides a new and effective strategy for the treatment of bone defects.

Physically cross-linked scaffold composed of hydroxyapatite-chitosan-alginate-polyamide has potential to trigger bone regeneration in craniofacial defect

Abstract Recently, the fabrication of a scaffold from biomaterials has been increased due to the lack of adequate natural bone for grafting. In this study, hydroxyapatite-chitosan-alginate-polyamide (HCAP) synthetic scaffold was fabricated using the thermally induced phase separation (TIPS) technique. The scaffold was cross-linked with either a chemical cross-linker (calcium chloride, 2-hydroxyethyl methacrylate (HEMA), or glutaraldehyde (GTA)) or a physical cross-linker (gamma irradiation (IR)) resulting in scaffolds HCAP-CaCl2, HCAP-HEMA, HCAP-GTA, and HCAP-IR, respectively. The cross-linked scaffolds were characterized based on physicochemical properties, cytotoxicity, and biocompatibility. HCAP-GTA showed the highest density and the lowest swelling ratio and biodegradation rate closely matching with those of the HCAP-IR. Porosity and density of the HCAP, HCAP-IR, and HCAP-GTA scaffolds were 92.14, 87.26, and 83.33 %, and 0.241, 0.307, and 0.335 g/cm3, respectively. The swelling ratio for the same scaffolds was 149, 110, and 108 % after 72 h of observation. Brine shrimp cytotoxicity and RBC biocompatibility assay confirmed the non-toxic nature of HCAP-IR and HCAP-GTA scaffolds. The HCAP-IR scaffold was tested for bone regeneration in the rabbit mandible defect model. Histological analysis revealed the regeneration of new bone and restoration of bone defect at the site of injury. These findings indicate that radiation induced physically cross-linked HCAP scaffold could be used as an alternative in bone defect replacement therapy.

Natural Polymers with Bioactive Glass Additives for Bone Regeneration: Chemistry and Trends

Abstract: Natural polymers, such as chitosan (CH) and gelatine (GE), have a wide range of uses in biological environments. This is primarily attributed to their biocompatibility and the body’s recognition of them being as “self” as opposed to “foreign”. These polymers provide a dynamic and cell-friendly interaction environment which is a crucial factor for tissue repair and regeneration. Bone regeneration is a highly intricate multistep process involving a plethora of biomolecules, signalling pathways, and stages in cellular activity. Critically-sized bone defects do not regenerate without an implant due to the cessation of the cellular stimulus associated with new bone formation. Therefore, natural polymers have been combined with bioactive glasses (BGs) to provide a biocompatible delivery matrix and to stimulate bone formation via the release of osteogenic ions from the BG particles. The addition of BG particles in natural polymers has been shown not only to result in an osteogenic response at a cellular level but also result in per se formation of hydroxyapatite (HA) on implant surfaces and regeneration of new bone in vivo. This review discusses the recent trends over the last decade in this field, keeping a focus on the chemistry and properties of CH and GE composites containing a bioactive glass additive.

Cross Talk Between Cells and the Current Bioceramics in Bone Regeneration: A Comprehensive Review.

The conventional approach for addressing bone defects and stubborn non-unions typically involves the use of autogenous bone grafts. Nevertheless, obtaining these grafts can be challenging, and the procedure can lead to significant morbidity. Three primary treatment strategies for managing bone defects and non-unions prove resistant to conventional treatments: synthetic bone graft substitutes (BGS), a combination of BGS with bioactive molecules, and the use of BGS in conjunction with stem cells. In the realm of synthetic BGS, a multitude of biomaterials have emerged for creating scaffolds in bone tissue engineering (TE). These materials encompass biometals like titanium, iron, magnesium, and zinc, as well as bioceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP). Bone TE scaffolds serve as temporary implants, fostering tissue ingrowth and the regeneration of new bone. They are meticulously designed to enhance bone healing by optimizing geometric, mechanical, and biological properties. These scaffolds undergo continual remodeling facilitated by bone cells like osteoblasts and osteoclasts. Through various signaling pathways, stem cells and bone cells work together to regulate bone regeneration when a portion of bone is damaged or deformed. By targeting signaling pathways, bone TE can improve bone defects through effective therapies. This review provided insights into the interplay between cells and the current state of bioceramics in the context of bone regeneration.

Alendronate-decorated strontium-containing bioactive glass nanoparticles with dual osteogenic and anti-osteoclastic effects for osteoporosis

Bioactive glass (BG) has emerged as a promising material for bone regeneration. In this study, strontium-doped bioactive glass nanoparticles loaded with alendronate (A-SrBG) were fabricated and characterized to evaluate their potential for bone regeneration in osteoporosis. A-SrBG nanoparticles have excellent bioactivity, inducing apatite mineralization and achieving sustained release of bioactive ions in vitro. Moreover, A-SrBG nanoparticles could promote the differentiation of osteoblasts while inhibiting the differentiation of osteoclasts by preventing RANKL-induced activation of the NF-κB and mevalonate pathways. A-SrBG nanoparticles could be phagocytosed into the cells and present in the cytoplasm, which could enhance the efficiency of ALN. When implanted in vivo, A-SrBG discs promoted the regeneration of new bone. The results demonstrated that the ability of A-SrBG to dually regulate both osteogenesis and osteoclastogenesis makes it a promising candidate for the reconstruction of bone defects in osteoporosis.

Promoting Stem Cell Mechanosensing and Osteogenesis by Hybrid Soft Fibers.

Bone regenerative biomaterials are essential in treating bone defects as they serve as extracellular matrix (ECM) mimics, creating a favorable environment for cell attachment, proliferation, and differentiation. However, the currently used bone regenerative biomaterials mostly exhibit high stiffness, which may lead to difficulties in degradation and thus increase the risk of foreign body ingestion. In this study, we prepared soft fibrous scaffolds modified with Zn-MOF-74 nanoparticles via electrostatic spinning. The soft fibers (only 1 kPa) permit remodeling under cellular adhesive force, optimizing the mechanical cues in the microenvironment to support cell adhesion and mechanosensing. In addition, the incorporation of Zn-MOF-74 nanoparticles enables the stable and sustained release of zinc ions, promoting stem cell mechanotransduction and osteogenic differentiation. Therefore, the hybrid soft fibers facilitate the regeneration of new bone in the rat femoral defect model, which provides a promising approach for regenerative medicine.

Triple-layered scaffold containing cisplatin and curcumin applied for cancerous bone regeneration.

Novel drug delivery system was prepared and evaluated as for application in cancerous bone treatment. It had three stacked layers, including a drug-free layer, a cisplatin-loaded layer, and a curcumin-containing layer. Our previously characterized biomaterials, namely Zr-hydroxyapatite (Zr-HA) and alkaline-treated polycaprolactone (modified-PCL), were used as major components of the drug carrier. Polar-polar interactions between cisplatin and Zr-HA were modulated by the modified-PCL included, leading to increase of cisplatin release. Using β-cyclodextrin (β-CD) to entrap curcumin caused improvement of curcumin solubility and release. The 3D-construct was porous with internal interconnected pores according to SEM micrographs. Large amount of apatite was formed and proteins adsorbed on the scaffolds after immersed in physiologic buffer solution and in medium containing fetal bovine serum, respectively. Optimal concentrations of ascorbic acid and triamcinolone were used for induction of bone marrow stromal cells to become osteoblasts by expressing an enzyme marker, e.g., alkaline phosphatase. The prepared scaffolds were considered osteo-conductive and osteo-inductive. The concentrations of cisplatin and curcumin reached the IC50 of SK-ES-1 cells of osteosarcoma and MCF-7 cells of breast adenocarcinoma after 24h and 3days of release, respectively. These cancer cells were more sensitive to the combined cisplatin and curcumin than each of the drugs. Regeneration of new bone and execution of residential cancer cells in defected bone were proposed after replacing the lost bone by this established drug carrier. The assumption needs to be verified in the future using animal models.

A Novel Porous Butyryl Chitin-Animal Derived Hydroxyapatite Composite Scaffold for Cranial Bone Defect Repair.

Bone defects, a common orthopedic problem in clinical practice, are a serious threat to human health. As alternative materials to autologous bone grafts, synthetic cell-free functionalized scaffolds have been the focus of recent research in designing scaffolds for bone tissue engineering. Butyryl chitin (BC) is a derivative of chitin (CT) with improved solubility. It has good biocompatibility, but few studies have investigated its use in bone repair. In this study, BC was successfully synthesized with a degree of substitution of 2.1. BC films were prepared using the cast film method and showed strong tensile strength (47.8 ± 4.54 N) and hydrophobicity (86.4 ± 2.46°), which was favorable for mineral deposition. An in vitro cytological assay confirmed the excellent cell attachment and cytocompatibility of the BC film; meanwhile, in vivo degradation indicated the good biocompatibility of BC. Hydroxyapatite (HA), extracted from bovine cancellous bone, had good cytocompatibility and osteogenic induction activity for the mouse osteoblast cell line MC3T3-E1. With the aim of combining the advantages of BC and HA, a BC-HA composite scaffold, with a good pore structure and mechanical strength, was prepared by physical mixing. Administered into skull defects of rats, the scaffolds showed perfect bone-binding performance and effective structural support, and significantly promoted the regeneration of new bone. These results prove that the BC-HA porous scaffold is a successful bone tissue engineering scaffold and has strong potential to be further developed as a substitute for bone transplantation.

Porcine Cortical Bone Lamina as a Predictable Technique for Guided Bone Regeneration: Histomorphometric and Radiographic Evaluation

The stability of bone regenerated through Guided Bone Regeneration (GBR) around implants is crucial for long-term success. In this case series, changes in marginal bone levels (MBL) around implants placed in a regenerated bone using heterologous cortical lamina technique were radiographically measured. In addition, bone samples were obtained and submitted to histological and histomorphometric analysis. Thirty implants were placed in regenerated bone sites 8 months after the regenerative surgery; in the same surgical stage, a hard tissue biopsy was taken using a trephine bur and submitted to histologic and histomorphometric analysis. Changes in the marginal bone level, mesial and distal to the implant shoulder, were measured between prosthetic loading and the last follow-up, 2 years later. No implants were lost, and all could be deemed successful at the last follow-up. Only a minimal mean variation in the position of the marginal bone level was observed, both at the mesial (0.11 ± 0.49 mm) and at the distal level (0.03 ± 0.19 mm). The bone lamina had been resorbed after 8 months, and new bone had developed in close connection to the biomaterial. The average percentage of newly formed bone was 28%, while only 10% of the samples were composed of residual biomaterial; bone marrow and connective tissue composed the remaining part of the samples. This regeneration technique allowed, thanks to the rigidity of the lamina, the regeneration of new bone, which is stable after the prosthetic load. Further studies are needed to compare this procedure with those adopting non-resorbable, titanium-supported membranes.

Hierarchical Intrafibrillarly Mineralized Collagen Membrane Promotes Guided Bone Regeneration and Regulates M2 Macrophage Polarization.

Mineralized collagen has been introduced as a promising barrier membrane material for guided bone regeneration (GBR) due to its biomimetic nanostructure. Immune interaction between materials and host significantly influences the outcome of GBR. However, current barrier membranes are insufficient for clinical application due to limited mechanical or osteoimmunomodulatory properties. In this study, we fabricated hierarchical intrafibrillarly mineralized collagen (HIMC) membrane, comparing with collagen (COL) and extrafibrillarly mineralized collagen (EMC) membranes, HIMC membrane exhibited preferable physicochemical properties by mimicking the nanostructure of natural bone. Bone marrow mesenchymal stem cells (BMSCs) seeded on HIMC membrane showed superior proliferation, adhesion, and osteogenic differentiation capacity. HIMC membrane induced CD206+Arg-1+ M2 macrophage polarization, which in turn promoted more BMSCs migration. In rat skull defects, HIMC membrane promoted the regeneration of new bone with more bone mass and more mature bone architecture. The expression levels of Runx2 and osterix and CD68 + CD206 + M2 macrophage polarization were significantly enhanced. HIMC membrane provides an appropriate osteoimmune microenvironment to promote GBR and represents a promising material for further clinical application.

Rhizoma drynariae total flavonoids combined with calcium carbonate ameliorates bone loss in experimentally induced Osteoporosis in rats via the regulation of Wnt3a/\u03b2-catenin pathway

BackgroundRhizoma drynariae, a traditional Chinese herb, is commonly used in treatment of bone healing in osteoporotic fractures. However, whether the Rhizoma drynariae total flavonoids (RDTF) can promote the absorption of calcium and enhance the bone formation is unclear. The aim of the present study was to investigate the preventive effects of RDTF combined with calcium carbonate (CaCO3) on estrogen deficiency-induced bone loss.MethodsThree-month-old Sprague–Dawley rats were ovariectomized (OVX) and then treated with CaCO3, RDTF, and their admixtures for ten weeks, respectively. The bone trabecular microstructure, bone histopathological examination, and serum biomarkers of bone formation and resorption were determined in the rat femur tissue. The contents of osteoprotegerin (OPG), receptor activator of the NF-κB (RANK), and its ligand (RANKL) in marrow were analyzed by ELISA, and the protein expressions of Wnt3a, β-catenin, and phosphorylated β-catenin (p-β-catenin) were analyzed by Western blot. Statistical analysis was conducted by using one-way analysis of variance (ANOVA) followed by LSD post hoc analysis or independent samples t test using the scientific statistic software SPSS version 20.0ResultsRDTF combined with CaCO3 could promote osteosis and ameliorate bone loss to improve the repair of cracked bone trabeculae of OVX rats. Furthermore, RDTF combined with CaCO3 also could prevent OVX-induced decrease in collagen fibers in the femoral tissue of ovariectomized rats and promote the regeneration of new bone or cartilage tissue, while CaCO3 supplementation promoted the increase in bone mineral content. Nevertheless, there was no difference in the expression of Wnt3a, β-catenin and p-β-catenin between osteopenic rats and RDTF treated rats, but RDTF combined with CaCO3 could activate the Wnt3a/β-catenin pathway.ConclusionsRDTF combined with CaCO3 could ameliorate estrogen deficiency-induced bone loss via the regulation of Wnt3a/β-catenin pathway.

Degradation mechanisms and acceleration strategies of poly (lactic acid) scaffold for bone regeneration

Poly (lactic acid) (PLA) with good biodegradability, biocompatibility and processability has a wide application prospect in bone tissue engineering. However, PLA exhibits a very slow degradation rate, hindering the regeneration of new bone. In this study, the degradation mechanisms of PLA bone scaffold, including autocatalysis and non-catalysis, end-chain and random chain breaking, surface degradation and bulk degradation, were analyzed systematically, and the influence factors including crystallinity, molecular weight, pH, and so on, were introduced. On this basis, the strategies including blending, copolymerization, compounding and surface modification to accelerate the degradation of PLA were summarized, and the accelerating mechanisms were analyzed and discussed detailedly. In addition, rapid prototyping technologies with unique advantages on the structure and shape of scaffold were introduced. The mechanical properties (strength and modulus) and biological properties (in vivo and in vitro) of PLA scaffold were reviewed and discussed. Finally, the present problem of research including the simultaneous improvement of mechanical and degradation properties was put forward, and four-dimensional printing (4D printing) as an advanced technique which might bring new ideas to improve and extend the properties of PLA scaffold was mentioned.

Calcium Sulfate as a Scaffold for Bone Tissue Engineering: A Descriptive Review

In regenerative approaches, scaffolds play a crucial role in defining the 3-D anatomical shape and microenvironment for regenerative cells, while maintaining space, favoring regeneration of new bone, and preventing soft tissue migration in the bony lesion. A variety of materials have been explored as scaffolds for bone tissue regeneration. Metals are generally inappropriate for such applications because they lack the desired degradability in a biological environment requiring a second surgery. Synthetic polymers can provide physical strength and engineered chemical properties however, they do not have optimal ease of handling or predictable biodegradation rate. In contrast to these scaffolds, calcium sulfate, also known as Plaster of Paris, is a highly biocompatible and biodegradable material that is one of the simplest synthetic bone-like grafts. It has been sued as a graft material in orthopedics and dentistry for more than one hundred years. The present review illustrates and examines current advances regarding calcium sulfate sources, various properties,scaffold forms, and clinical applications for bone tissue engineering.Additionally,it also describesNanocrystallinecalcium sulfate. Keywords: Calcium sulfate; Gypsum; Plaster of Paris; Graft; Regeneration

Three-dimensional assessment of root migration and rotation patterns after coronectomy: bone-embedded roots versus soft tissue-covered roots

In this study, a three-dimensional evaluation was performed to explore differences between bone-embedded and soft tissue-covered roots after mandibular third molar (M3M) coronectomy. Patients were recruited according to the results of cone-beam computed tomography, 6 months after coronectomy. Completely bone-embedded M3Ms were assigned to group B, while completely soft tissue-covered M3Ms were assigned to group S. Data were recorded using digital software. A total of 213 M3Ms in 181 patients were investigated, of which 170 were assigned to the two study groups. Age was the primary factor influencing root migration (P<0.001). The smaller the degree of angulation of the M3M, the more likely was the root complex to rotate distally (r=−0.37, P<0.001). The depth of the impacted M3M contributed to the regeneration of new bone (P≤0.008). The length of the root complex (odds ratio 0.82, P=0.048) and distance from the root to the alveolar crest (odds ratio 1.23, P=0.026) were two critical factors influencing whether the root complex was bone-embedded. Ensuring that the length of the root complex is <7.6mm and the distance between the root and alveolar crest is ≥5mm were both found to be critical to the remaining root being completely bone-embedded and thus preventing eruption and the need for secondary surgery.

Mobilization of Transplanted Bone Marrow Mesenchymal Stem Cells by Erythropoietin Facilitates the Reconstruction of Segmental Bone Defect.

Reconstruction of segmental bone defects poses a tremendous challenge for both orthopedic clinicians and scientists, since bone rehabilitation is requisite substantially and may be beyond the capacity of self-healing. Bone marrow mesenchymal stem cells (BMSCs) have been identified as an optimal progenitor cell source to facilitate bone repair since they have a higher ability for proliferation and are more easily accessible than mature osteoblastic cells. In spite of the potential of BMSCs in regeneration medicine, particularly for bone reconstruction, noteworthy limitations still remain in previous application of BMSCs, including the amount of cells that could be recruited, the compromised bone migration of grafted cells, reduced proliferation and osteoblastic differentiation ability, and likely tumorigenesis. Our current work demonstrates that BMSCs transplanted through the caudal vein can be mobilized by erythropoietin (EPO) to the bone defect area and participate in regeneration of new bone. Based on the histological analysis and micro-CT findings of this study, EPO can dramatically promote the effects on the osteogenesis and angiogenesis efficiency of BMSCs in vivo. Animals that underwent EPO+BMSC administration demonstrated a remarkable increase in new bone formation, tissue structure organization, new vessel density, callus formation, and bone mineral density (BMD) compared with the BMSCs alone and control groups. At the biomechanical level, we demonstrated that combing transplantation of EPO and BMSCs enhances bone defect reconstruction by increasing the strength of the diaphysis, making it less fragile. Therefore, combination therapy using EPO infusion and BMSC transplantation may be a new therapeutic strategy for the reconstruction of segmental bone defect.

Blastema formation and periosteal ossification in the regenerating adult mouse digit.

While mammals cannot regenerate amputated limbs, mice and humans have regenerative ability restricted to amputations transecting the digit tip, including the terminal phalanx (P3). In mice, the regeneration process is epimorphic and mediated by the formation of a blastema comprised of undifferentiated proliferating cells that differentiate to regenerate the amputated structures. Blastema formation distinguishes the regenerative response from a scar-forming healing response. The mouse digit tip serves as a preclinical model to investigate mammalian blastema formation and endogenous regenerative capabilities. We report that P3 blastema formation initiates prior to epidermal closure and concurrent with the bone histolytic response. In this early healing response, proliferation and cells entering the early stages of osteogenesis are localized to the periosteal and endosteal bone compartments. After the completion of stump bone histolysis, epidermal closure is completed and cells associated with the periosteal and endosteal compartments blend to form the blastema proper. Osteogenesis associated with the periosteum occurs as a polarized progressive wave of new bone formation that extends from the amputated stump and restores skeletal length. Bone patterning is restored along the proximal-distal and medial digit axes, but is imperfect in the dorsal-ventral axis with the regeneration of excessive new bone that accounts for the enhanced regenerated bone volume noted in previous studies. Periosteum depletion studies show that this compartment is required for the regeneration of new bone distal to the original amputation plane. These studies provide evidence that blastema formation initiates early in the healing response and that the periosteum is an essential tissue for successful epimorphic regeneration in mammals.

Fabrication of 3D porous poly(lactic acid)-based composite scaffolds with tunable biodegradation for bone tissue engineering

Success of biomimetic scaffold relies on the comparability of its microarchitecture and physicochemical properties to the natural bone. However, porous scaffolds which simultaneously possessed excellent mechanical properties, favorable bioactivity and tunable biodegradation were rarely reported. Herein, to integrate the high stiffness of hydroxyapatite (HA), the formability of lignocellulose (LG), the processability of poly(lactic acid) (PLA) and the bioactivity of sol-gel derived 58S bioactive glass (BG), poly(lactic acid) (PLA)-based composite scaffolds were fabricated by a simple technique of combining the solvent casting/particulate leaching and sol-gel method. The resultant scaffolds showed well-defined interconnected porous structure with pore size of 200–400 μm and rough pore wall, which was reported to be potentially beneficial for cell adhesion and ingrowth. In addition, the mechanical properties were obviously improved by the reinforcements of LG, HA, and BG. In vitro biomineralization studies indicated the incorporation of BG significantly enhanced the bioactivity of composite scaffolds. Specially, the degradation rate of scaffolds could be easily regulated by adjusting the BG content to match the regeneration of new bone. The developed PLA-based composite scaffolds might have a great potential for bone regeneration.

Biocompatibility of Yttria-Tetragonal Zirconia Polycrystal Seeded with Human Adipose Derived Mesenchymal Stem Cell.

Introduction:The scaffold is a place for regeneration of new bone and bone tissue growths in tissue engineering applications. hADMSC is a multipotent cell which can differentiate into osteogenic, chondrogenic and adipogenic. Y-TZP has been shown to have several advantages over other ceramics because of its hard nature, namely fracture toughness and high flexural strength.Aim:This study aimed to analyze the biocompatibility of Y-TZP as a scaffold seeded with hADMSCs by in vitro analysis.Material and methods:This research involved several processes, namely Y-TZPS manufacture process, XRD examination, differentiation and characterization of hADMSC, SEM observation, and then TT.Results:The results of the XRD examination showed that Y-TZPSs had sharp peaks. It suggests that they had high crystal purity. The marked expression of the characterization of hADMSC is the positive expression of Cluster of differentiation (CD), namely CD 90, CD 73 and CD 105 above NMT and negative expressions of CD 14, CD 19, CD 34, CD 45 and also HLA-DR below NLT. The analysis of observations on the Y-TZPSs with SEM, subsequently, indicated the porosity of Y-TZPSs, as a result, the adhesion of HADMSCs occurred and grew in the porosity in the Y-TZPSs.Conclusions:Y-TZPSs with low porosity and toxicity can be able to proliferate and differentiate if seeded with hADMSC. Y-TZPSs are expected to be used as implantable biomaterials using hADMSCs with high biocompatibility.

3D-Printed High Strength Bioactive Supramolecular Polymer/Clay Nanocomposite Hydrogel Scaffold for Bone Regeneration.

The emerging 3D bioprinting technique that is strongly dependent on the development of bioinks offers a promising opportunity to customize personalized bioscaffolds for precision and individualized therapy of bone defects. Hydrogels are one sort of attractive scaffolding materials due to their resemblance to extracellular matrices. Although much progress has been made in designing and fabricating high strength hydrogels, very few of them have been extended to the treatment of bone defects. In this work, we developed a hybrid bioink composed of a hydrogen bonding monomer (N-acryloyl glycinamide) (NAGA) and nanoclay. The hybrid ink could be conveniently tailored as a high strength PNAGA-Clay composite scaffold under UV light illumination of printed prehydrogel. The hydrogen bonding combined with physical cross-linking of nanoclay contributed to the superior mechanical performances as well as swelling stability of the hydrogels and bioscaffols. The sustainable release of intrinsic Mg2+ and Si4+ from the PNAGA-Clay scaffold was shown to promote the osteogenic differentiation of primary rat osteoblast (ROB) cells. Importantly, this implantable PNAGA-Clay scaffold highly efficiently facilitated the regeneration of new bone in tibia defects of rats. We anticipate that hybridization of the hydrogen bonding monomer with a variety of bioactive inorganic nanoparticles will offer new possibilities to develop numerous bioinks for 3D-printing of desired bioscaffolds to realize individualized repair of degenerated load-bearing tissues.

Test in canine extraction site preservations by using mineralized collagen plug with or without membrane.

The aim of this study was to discuss the feasibility of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration membrane in site preservation in extraction sockets. The third mandibular premolars on both sides were extracted from four dogs, thus there were 16 alveolar sockets in all dogs and were randomly assigned into three groups. Group A had six alveolar sockets, and groups B and C had five alveolar sockets, respectively. Each alveolar socket of group A was immediately implanted with a porous mineralized collagen plug and covered with a bilayer mineralized collagen-guided bone regeneration membrane after tooth extraction. Alveolar sockets of group B were implanted with porous mineralized collagen plug only, and group C was set as blank control without any implantation. The healing effects of the extraction sockets were evaluated by gross observation, morphological measurements, and X-ray micro-computed tomography after twelve weeks. Twelve weeks after operation, both groups A and B had more amount of new bone formation compared with group C; in terms of the degree of alveolar bone height, group A was lower than groups B and C with significant differences; the bone mineral density in the region of interest and bone remodeling degree in group A were higher than those of groups B and C. As a result, porous mineralized collagen plug could induce the regeneration of new bone in extraction socket, and combined use of porous mineralized collagen plug and bilayer mineralized collagen guided bone regeneration membrane could further reduce the absorption of alveolar ridge and preserve the socket site.