Bone Regeneration Research Articles

3D-printed polycaprolactone/collagen/alginate scaffold incorporating phlorotannin for bone tissue regeneration: Assessment of sub-chronic toxicity

The development of effective scaffolds for bone regeneration is crucial given the increasing demand for innovative solutions to address bone defects and enhance healing process. In this study, a polycaprolactone/fish collagen/alginate (P/FC/A) 3D scaffold incorporating phlorotannin was developed to promote bone tissue regeneration. While the efficacy of the P/FC/A scaffold has been demonstrated through in vitro and in vivo experiments, its sub-chronic toxicity in animal models remains understudied, raising concerns regarding its safety in clinical application. Therefore, this study assessed the sub-chronic toxicity of the P/FC/A scaffold over 12 week using a New Zealand White rabbit model. Our results indicate no significant adverse effects in the group exposed to the P/FC/A scaffold compared with the negative control group implanted with a high-density polyethylene scaffold. These findings underscore the non-toxicity and safety profile of the P/FC/A scaffold, further supporting its potential suitability for clinical use in bone regeneration.

Development of liposomal amniotic mesenchymal stem cell metabolite products (AMSC-MP) loaded-scaffold for in vitro osteogenesis induction

The use of scaffolds with good biocompatibility and mechanical properties largely determines the success of bone defect therapy intended to improve quality-adjusted life years. Furthermore, amniotic mesenchymal stem cell metabolite product (AMSC-MP) is required to accelerate bone regeneration with sustained release required to maximize the effectiveness of therapy. This study aims to evaluate the effect of different phospholipids on the osteogenesis capacity of AMSC-MP liposome loaded into scaffold. The thin layer hydration method was employed to create the AMSC-MP liposomes which had different lipid components: L-α-phosphatidylcholine (PC) an unsaturated or hydrogenated soybean phosphatidylcholine (HSPC), a saturated phospholipid, with different types of charged phospholipids i.e., 1,2-dioleoyltrimethylammoniumpropane (DOTAP) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), which were cationic and non-ionic lipids respectively.AMSC-MP liposomes were embedded in the scaffold during a 24-hour incubation period. The results indicated that the particle sizes of liposomes prepared with saturated phospholipids, HS-DOTAP (132.35 ± 2.75 nm) and HS-DOTAP (152.85 ± 5.86 nm) were larger than those with saturated phospholipids, namely PC-DOTAP (139.355 ± 2.75 nm) and PC-DOTAP (91.85 ± 0.07 nm). The use of DOTAP in AMSC-liposomes resulted in positively charged vesicles i.e., +5 mV for HSPC-DOTAP and + 10 mV for PC-DOTAP. Moreover, the results of an MTT viability test conducted on 7f2 cells and MSC indicated that all the formulas demonstrate good in vitro biocompatibility. Formulations containing DOPE produced high cellular uptake values and had superior sustain release properties compared to the others. This result correlates positively with cell attachment to the liposome scaffold which was higher than the others. Moreover, DOPE-containing formulations increased RUNX2 expression, indicating enhanced in vitro osteogenesis capacity. Therefore, Liposome AMSC-MP loaded scaffold demonstrates high potential for use in bone regeneration therapy.

Uniaxial static strain enhances osteogenic and angiogenic potential under hypoxic conditions in distraction osteogenesis

ObjectiveBone incision leads to interrupted and sluggish blood flow in the process of distraction osteogenesis (DO), creating a hypoxia (0–2% oxygen tension) at the center of the bone callus. This hypoxia is critical in the coupling of osteogenesis and angiogenesis during DO. This study aimed to investigate the effect of Uniaxial Static Strain (USS) on osteogenesis in osteoblasts under hypoxic conditions, with a focus on the expression of osteogenic markers and angiogenic factors.MethodsThe USS was made by a multi-unit tension compression device.Osteoblasts were subjected to 10% USS made under hypoxic conditions to mimic the process of DO in vitro. The cell proliferation, alkaline phosphatase (ALP) activity, mineralized nodule formation, and expression of osteogenic and angiogenic markers were evaluated by using a CCK-8 assay, alkaline phosphatase (ALP) staining, ALP activity assay, alizarin red S staining, qRT-PCR, Western blotting and ELISA.ResultsHypoxia inhibited osteoblast cell proliferation, ALP activity, mineralized nodule formation, and the expression of runt-related transcription factor 2 (Runx- 2), osteopontin(OPN), osteocalcin (OCN), collagen type I (Col1a1). Conversely, hypoxia upregulated the expression of hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF), which are associated with angiogenesis. However, the application of USS enhanced osteoblasts’ osteogenic capacity and upregulated angiogenic factors under hypoxic conditions.ConclusionUSS can enhance osteogenesis in osteoblasts under hypoxic conditions. Moreover, it may stimulate angiogenesis by promoting the expression of VEGF, which further contributes to bone formation. This finding provides important implications for understanding the mechanisms involved in bone regeneration and may have clinical applications in optimizing the effectiveness of DO techniques.

3D-printed porous calcium silicate scaffolds with hydroxyapatite/graphene oxide hybrid coating for guided bone regeneration

Calcium silicate (CS) is a suitable bone repair material due to its bioactivity and biocompatibility. However, its rapid degradation rate and poor cell response affect the bone regeneration process. Surface modification of implants represents a potent strategy for enhancing the performance of biomaterials. Here, we present a novel method combining hydrothermal treatment and chemical grafting to tailor the surface morphology and composition of 3D-printed calcium silicate porous scaffolds. The resulting scaffold surface features hydroxyapatite (HA) nanosheets and graphene oxide (GO) sheet structures. Surface modification significantly reduced the degradation rate of CS scaffolds and decreased the Si ion concentration after PBS immersion, which was more conducive to cell survival. Our findings reveal that the CS/HA/GO scaffold exhibits superior biocompatibility and significantly enhances cell adhesion, proliferation, and osteogenic differentiation. In vivo studies demonstrate that the CS/HA/GO scaffold markedly promotes the regeneration of defective bone tissue. This work highlights the potential of HA and GO coatings on interconnected porous scaffolds to induce bone tissue regeneration, offering a promising strategy for orthopedic applications.

FRESH 3D printing of zoledronic acid-loaded chitosan/alginate/hydroxyapatite composite thermosensitive hydrogel for promoting bone regeneration

The aim of this study was to develop a composite thermosensitive hydrogel for bone regeneration applications. This hydrogel consisted of chitosan, alginate and hydroxyapatite, and was loaded with zoledronic acid as a model drug. The feasibility of three-dimensional (3D) printing of the thermosensitive hydrogel using the extrusion technique was investigated. The 3D printing technique called Freeform Reversible Embedded Suspended Hydrogel (FRESH) printing was employed for this purpose. To characterize the composite hydrogels, several tests were conducted. The gelation time, rheological properties, and in vitro drug release were analyzed. Additionally, the cell viability test on human osteosarcoma MG-63 cells for the composite hydrogel was assessed using an MTT assay. The results of the study showed that the zoledronic acid-loaded composite thermosensitive hydrogel was successfully printed using the FRESH 3D printing technique which was not possible otherwise i.e., by using traditional 3D printing techniques. Further examination of the printed constructs using a Scanning Electron Microscope revealed the presence of porous and layered structures. The gelation times of the composite thermosensitive hydrogel was determined to be 10 and 20 min, respectively for scaffolds with and without HA, indicating the successful formation of the gel within a reasonable time to the FRESH technique. The flow behavior of the hydrogel was found to be pseudoplastic, following a non-Newtonian flow pattern with Farrow’s constant (N) values of 1.708 and 1.853 for scaffolds with and without hydroxyapatite, respectively. In terms of drug release, scaffolds prepared with and without hydroxyapatite reached nearly 100% of zoledronic acid release in 360 h and 48 h, respectively. The cell viability test on human osteosarcoma MG-63 cells using MTT assay has shown increased cell viability % in the case of the composite hydrogel, indicating a biocompatible scaffold. Overall, this study successfully developed a composite thermosensitive hydrogel loaded with zoledronic acid for bone regeneration applications and 3D printed using the FRESH 3D printing technique. The results of this study provide valuable insights into the potential use of this composite hydrogel for future biomedical applications.

β-Tricalcium phosphate incorporated natural rubber latex membranes for calvarial bone defects: Physicochemical, in vitro and in vivo assessment

Natural rubber latex membrane (NRL) is a biocompatible macromolecule that stimulates angiogenesis and promotes bone repair. Similarly, β-tricalcium phosphate (β-TCP) is an osteoconductive and osteoinductive bioceramic widely used as a bone substitute. Here, we investigated the combined use of these biomaterials in the guided bone regeneration process for calvarial defects in rats. Physicochemical characterization was performed to evaluate the interaction between β-TCP and NRL. Membrane toxicity was assessed using MC3T3 osteoblasts culture and in vivo assays with Caenorhabditis elegans. Lastly, NRL membranes, NRL incorporated with β-TCP membranes (NRL-β-TCP), and a periosteum-only (control group) were tested on rodents. MC3T3 cells adhered to membranes, preserving their morphology and intercellular connections. NRL-β-TCP membranes demonstrated no toxicity in larvae, which maintained their sinusoidal wave shape. Tests results on rodents revealed statistical difference between the groups at 60 days post-operation. NRL-β-TCP (56.1 ± 14.0 %) had an average 1.48-fold higher than the control group (38.0 ± 9.1 %), with tissue production and bone remodeling. Our qualitative histological analyses revealed that membranes significantly accelerated bone formation without any signs of inflammatory reactions. We conclude that NRL-β-TCP has potential to be used for flat bone regeneration, with osteoconductive properties, being a cheap, biocompatible, and effective occlusive barrier.

Harnessing Hydrogen Sulfide in Injectable Hydrogels That Guide the Immune Response and Osteoclastogenesis Balance for Osteoporosis Treatment

Elevated levels of oxidative stress, inflammation, and a dysregulated osteoclastogenesis balance frequently characterize the microenvironment of osteoporosis, which impedes the processes of healing and repair. Existing treatment approaches are limited in scope and rely primarily on factors and drugs. An injectable hydrogel designed for the ROS-responsive release of H2S gas is presented in this study. The first network of the hydrogel comprises sodium alginate (SA-SATO) chelated with S-aroylthiooxime (SATO) and an H2S-generating group, while the second network is composed of photocrosslinkable PEGDA. Through the integration of Cys-releasing microspheres that are reactive with ROS, a composite hydrogel was developed that exhibited advantageous mechanical characteristics and biosafety. The composite hydrogel effectively promoted osteogenic differentiation of mesenchymal stem cells, modulated macrophage polarization, decreased inflammatory responses, and halted cell apoptosis, as evidenced by in vitro experiments. Additionally, it released H2S gas and mitigated excess ROS in cells. The efficacy of the composite hydrogel in promoting bone defect repair and regeneration in an osteoporotic model was further validated by in vivo findings. In summary, the composite hydrogel exhibits potential as a viable approach to address osteoporotic bone defects by harmonizing osteogenesis and osteoclast activity, modulating the microenvironment of bone injuries, and reducing inflammation. Consequently, it presents a viable strategy for the efficient repair of bone defects.

Iron Chelators Augment Large Osteochondral Allograft Osseointegration in a Preclinical Canine Model.

Osteochondral allograft transplantation (OCAT) can be a successful joint restoration treatment option for large post-traumatic articular defects but is still associated with significant revision and failure rates. Despite recent advances that have improved OCAT success, insufficient osteochondral allograft (OCA) osseointegration remains a major cause of failure. Deferoxamine (DFO) is an effective angiogenic and osteo-anabolic iron chelator that consistently promotes bone neovascularization and regeneration. This study was designed to investigate local delivery of DFO for augmenting OCA osseointegration using a preclinical canine model for OCAT in the knee and hip as commonly affected joints. On Institutional Animal Care and Use Committee (IACUC) approval, 12 purpose-bred dogs underwent OCAT of the femoral head or femoral condyles with DFO or DFO-free (controls) microspheres in recipient sites. OCA revascularization, cellular repopulation, and integration were evaluated based on functional, diagnostic imaging, microcomputed tomography, histology, and immunohistochemistry outcome measures. Local delivery of DFO into OCAT recipient sites was associated with maintained or improved joint function, superior radiographic appearance, significantly greater trabecular thickness, higher bone volume, and new bone ingrowth compared with DFO-free controls. OCA osseointegration is dependent on cellular repopulation and neovascularization, resulting in new bone ingrowth through creeping substitution, and insufficient osseointegration with resorption and subsidence of the OCA remains a major cause of failure after transplantation. The results of this study suggest that local delivery of DFO using a controlled microsphere release system may reduce resorption and improve revascularization and cellular repopulation to increase new bone ingrowth, potentially expediting OCA osseointegration after transplantation.

BMSCs-derived exosomes carrying miR-668-3p promote progression of osteoblasts in osteonecrosis of the femoral head: Expression of proteins CD63 and CD9

Recently, exosomes that are derived from bone marrow mesenchymal stem cells (BMSCs) have garnered considerable interest due to their significant roles in the processes of bone regeneration and repair. Among the various molecular components present within these exosomes, miR-668-3p has emerged as a pivotal microRNA that may be instrumental in modulating the function and proliferation of osteoblasts, the cells responsible for bone formation. The primary objective of this research was to examine the enhancing effects of BMSC-derived exosomes that are enriched with miR-668-3p on the advancement of osteoblasts in the context of osteonecrosis of the femoral head. Furthermore, the study aimed to analyze how the expression of specific exosomal proteins, namely CD63 and CD9, influences this biological process. To conduct the investigation, BMSCs were isolated from healthy rat models, followed by the extraction of their secreted exosomes. The subsequent phase of the study involved assessing the proliferation and differentiation of osteoblasts by introducing the exosomes enriched with miR-668-3p into an experimental setup representing osteonecrosis of the femoral head. The findings revealed that exosomes derived from BMSCs, which contained miR-668-3p, significantly enhanced the proliferation of osteoblasts as well as the expression of key osteogenic marker genes. Notably, the levels of CD63 and CD9 proteins were markedly increased in the treated groups, indicating that the mechanisms underlying this promotion might involve cell adhesion and the endocytic uptake of exosomes.

Incorporation of Cerium Oxide Nanoparticles into the Micro-arc Oxidation Layer Promotes Bone Formation and Achieves Structural Integrity in Magnesium Orthopedic Implants

Biodegradable metals offer significant advantages by reducing the need for additional surgeries following bone fixation. These materials, with their optimal mechanical and degradable properties, also mitigate stress-shielding effects while promoting biological processes essential for healing. This study investigated the in vitro and in vivo biocompatibility of ZK60 magnesium alloy coated with a micro-arc oxidative layer incorporated with cerium oxide nanoparticles in orthopedic implants. The results demonstrated that the magnesium substrate undergoes gradual degradation, effectively eliminating long-term inflammation during bone formation. The micro-arc oxidative coating forms a dense ceramic layer, acting as a protective barrier that reduces corrosion rates and enhances the biocompatibility of the magnesium substrate. The incorporation of cerium oxide nanoparticles improves the tribological properties of the coating, refining degradation patterns and improving osteogenic characteristics. Furthermore, cerium oxide nanoparticles enhance bone reconstruction by facilitating appropriate interconnections between newly formed bone and native bone tissue. Consequently, cerium oxide nanoparticles contribute to favorable biosafety outcomes and exceptional bone remodeling capabilities by supporting bone healing and sustaining a prolonged degradation process, ultimately achieving dynamic equilibrium in bone tissue formation. Statement of SignificanceThis study comprehensively examined the incorporation of ceria nanoparticles into biodegradable magnesium through a micro-arc oxidative process for use in orthopedic implants. This study conducted a comprehensive analysis involving material characterization, biodegradability testing, in vitro osteogenesis assays, and in vivo implantation, highlighting the potential benefits of the distinctive properties of ceria nanoparticles. This research emphasizes the ability of ceria nanoparticles to enhance the biodegradability of magnesium and facilitate remarkable bone regeneration, suggesting promising advantages for additive materials in orthopedic implants.

Multifunctional scaffolds of β-tricalcium phosphate/bioactive glass coated with zinc oxide and copper oxide nanoparticles

Incorporating nanoparticles into scaffolds with regenerative potential is a promissory strategy to provide them with antimicrobial activity. Bioceramics, such as β-tricalcium phosphate (β-TCP) and bioactive glasses (BGs), stand out among synthetic materials for bone regeneration. In this context, we report the incorporation of zinc oxide (ZnO) and copper oxide/copper nitrate (CuO/Cu2H3NO5) nanoparticles onto the surface of the β-TCP/BG scaffolds. This report addresses the physicochemical characterization of the scaffolds, their antimicrobial activity, and their response to MC3T3-E1 cells. Our findings show that the incorporation of both nanoparticles effectively inhibited S. aureus growth, including its biofilm formation. While the presence of the nanoparticles initially decreased MC3T3-E1 cell viability, cell proliferation improved with prolonged incubation. Overall, the β-TCP/BG_Zn and β-TCP/BG_Cu scaffolds showed an early antimicrobial response, aiding infection eradication, while also supporting cell proliferation over time.

3D-printed laponite bioceramic triply periodic minimal surface scaffolds with excellent bioactivity for bone regeneration

Laponite (LAP) is a promising biomaterial for bone regeneration due to its reliable biocompatibility and excellent osteoinductivity in bone tissue engineering. However, the personalized manufacture of LAP bioceramic scaffolds with controlled complex architecture and high porosity remains challenging. This study used vat photopolymerization (VPP) to manufacture LAP bioceramic scaffolds with high precision and biological activity. We first selected a 40 wt% LAP bioceramic slurry for subsequent VPP printing based on stability experiments and viscosity characterization results. The curing parameters of the photosensitive bioceramic slurry and the degassing sintering process were studied to ensure the quality of the ceramic green bodies. Then, we characterized the effects of different sintering temperatures (1150°C, 1200°C, 1250°C) on the crystalline phase composition, microstructure, and mechanical properties of the LAP bioceramic. The research showed that the densification and compressive strength of the LAP bioceramic sintered at 1250°C reached 2.51 g/cm3 and 15 Mpa, respectively. Finally, the bioceramic scaffolds with different sintering temperatures were co-cultured with rat bone marrow mesenchymal stem cells to detect biocompatibility. The results showed that the three groups of scaffolds enhanced cell proliferation, adhesion, and osteogenic capacity. In conclusion, the LAP bone scaffolds by VPP presented the potential for bone repair.

Electrophoretic deposition of curcumin-loaded mesoporous bioactive glass nanoparticle-chitosan composite coatings on titanium for treating tumor-induced bone defect

Clinical treatment of osteosarcoma (OS) presents significant challenges in postoperative tumor recurrence and large segmental bone defects, often necessitating joint replacement or artificial bone implantation to repair failed or defective bone tissue. At the same time, fibroblastic encapsulation can impede direct contact between implants and bones, leading to implant failure. To tackle these issues, mesoporous bioactive glass nanoparticles (MBN) were synthesized and then loaded with curcumin (CUR). Subsequently, chitosan (CTS) was chosen as the charger and coating matrix, and electrophoretic deposition (EPD) was utilized to fabricate a CTS-MBN-CUR composite coating with triple functionality on Ti implants aiming for OS-induced bone repair. MBN-CUR nanoparticles are encapsulated in CTS and uniformly distributed within the coating, achieving robust adhesion and long-term release of CUR. Concurrently, the developed CTS-MBN-CUR coating exhibits moderate hydrophilicity, and good bioactivity. Moreover, three different types of cells, MC3T3-E1, L929, and MG63 cells, were individually cultured with the composite coating and subjected to comprehensive cellular studies. The coating presented favorable bioactivities, and osteogenic performance, and the ability to resist the activity of fibroblast and OS cells. These findings suggest that CTS-MBN-CUR holds promising potential for bone regeneration following OS resection surgery.

Synergy of engineered gelatin methacrylate-based porous microspheres and multicellular assembly to promote osteogenesis and angiogenesis in bone tissue reconstruction

One of the key challenges in bone defects treatment is providing adequate and stable blood supply during new tissue regeneration. Mesenchymal stem cells (MSCs) and endothelial cells (ECs) have great potential to promote osteogenesis and angiogenesis during bone defect repair through paracrine effects, but their therapeutic efficacy depends on effective cellular assembly and delivery. In this work, we developed various microspheres with different pore sizes for multi-cellular delivery to enhance the angiogenic and osteogenic capability via combining microfluidic and gradient freeze-drying techniques. The particle and pore size of fabricated porous gelatin methacrylate (GelMA)-based hydrogel microspheres (PGMS) could be controllable through adjusting the freezing time of hydrogel microspheres, the range of particles and pores size are 150–250 μm and 10–100 μm with different freezing time from 0 min to 30 min. The optimized particle size (200.8 ± 14.2 μm) and pore size (11.2 ± 1.9 μm) were explored to promote cell assemble, adhesion, growth, and proliferation in the PGMS. Furthermore, the co-assembly and delivery of bone marrow mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) on the PGMS was achieved and an optimal cellular ratio of BMSCs to HUVECs (20:2) was established for co-culturing of them to achieve optimal paracrine effects, further promoting osteogenic differentiation and angiogenesis. Finally, results from both in vitro and in vivo experiments showed that the developed PGMS with co-assembly of BMSCs to HUVECs contributed to accelerate bone regeneration and vascularization process daringly, exhibited great potential in vascularized bone tissue reconstruction.

Surgical approach to management of oroantral communications. Case report

Abstract One of the most frequent post-extraction complications of posterior maxillary teeth is oroantral communication, which consists of direct communication between the maxillary sinus and the oral cavity. The recommendation is to make an immediate closure within the first 48 hours to avoid possible complications that may include an oroantral fistula or chronic sinus disease. Currently, different techniques have been described for closing communication, including various types of materials. Some of the techniques are exclusively oriented toward closure, while others seek to achieve bone regeneration by using bone substitutes for the subsequent placement of dental implants. The aim of this study is to describe a simple surgical technique for managing oroantral communication using a collagen sponge with hydroxyapatite and ribose and covering it with overlapping double layers of ribose cross-linked collagen membrane without fixation.

Electrospun Polylactic Acid/Polyethylene Glycol/ Silicate‐Chlorinated Bioactive Glass Composite Scaffolds for Potential Bone Regeneration

ABSTRACTThe integration of bioglass with polymers in tissue engineering scaffolds holds promise for enhancing bone regeneration. This study explores the fabrication and characterization of composite scaffolds comprising polylactic acid (PLA)/polyethylene glycol (PEG) fibers incorporated with silicate‐chlorinated bioglasses (45S5 and 58S). Electrospinning was utilized to produce the scaffolds, followed by physical–chemical and in vitro evaluations. Scanning electron microscopy (SEM) revealed uniform fiber formation, with bioglass incorporation observed in the composite groups. Bioglass incorporation led to a significant reduction in fiber diameter. Thermogravimetric analysis (TGA) estimated bioglass content, with 58S exhibiting the highest incorporation. Contact angle measurements indicated enhanced hydrophilicity in bioglass‐containing groups. In vitro, bioactivity assessment in simulated body fluid (SBF) demonstrated apatite formation potential and the pH variance indicates a slightly alkaline to neutral condition. Cell culture studies revealed robust cellular adhesion and metabolic activity across all groups, with no cytotoxic effects observed. Overall, these findings suggest the potential of PLA/PEG bioglass composite scaffolds for bone tissue engineering applications.

Impact of Porosity and Stiffness of 3D Printed Polycaprolactone Scaffolds on Osteogenic Differentiation of Human Mesenchymal Stromal Cells and Activation of Dendritic Cells.

Despite the potential of extrusion-based printing of thermoplastic polymers in bone tissue engineering, the inherent nonporous stiff nature of the printed filaments may elicit immune responses that influence bone regeneration. In this study, bone scaffolds made of polycaprolactone (PCL) filaments with different internal microporosity and stiffness was 3D-printed. It was achieved by combining three fabrication techniques, salt leaching and 3D printing at either low or high temperatures (LT/HT) with or without nonsolvent induced phase separation (NIPS). Printing PCL at HT resulted in stiff scaffolds (modulus of elasticity (E): 403 ± 19 MPa and strain: 6.6 ± 0.1%), while NIPS-based printing at LT produced less stiff and highly flexible scaffolds (E: 53 ± 10 MPa and strain: 435 ± 105%). Moreover, the introduction of porosity by salt leaching in the printed filaments significantly changed the mechanical properties and degradation rate of the scaffolds. Furthermore, this study aimed to show how these variations influence proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hBMSC) and the maturation and activation of human monocyte-derived dendritic cells (Mo-DC). The cytocompatibility of the printed scaffolds was confirmed by live-dead imaging, metabolic activity measurement, and the continuous proliferation of hBMSC over 14 days. While all scaffolds facilitated the expression of osteogenic markers (RUNX2 and Collagen I) from hBMSC as detected through immunofluorescence staining, the variation in porosity and stiffness notably influenced the early and late mineralization. Furthermore, the flexible LT scaffolds, with porosity induced by NIPS and salt leaching, stimulated Mo-DC to adopt a pro-inflammatory phenotype marked by a significant increase in the expression of IL1B and TNF genes, alongside decreased expression of anti-inflammatory markers, IL10 and TGF1B. Altogether, the results of the current study demonstrate the importance of tailoring porosity and stiffness of PCL scaffolds to direct their biological performance toward a more immune-mediated bone healing process.

Early anti-inflammatory polarization of macrophages ameliorates post-surgical inflammation and osseointegration around titanium implants in mice

Dental implants are considered a superior option for the replacement of missing teeth. However, the invasive nature of the surgical procedure often results in significant postoperative inflammation, and the prolonged healing period of 3 to 6 months presents a notable disadvantage. High mobility group box 1 (HMGB1) is a critical mediator of acute inflammation following surgical injury, which can hinder the onset of osseointegration. This study aims to examine whether the inhibition of HMGB1 can mitigate acute inflammation and subsequently enhance osseointegration. The findings indicate that HMGB1 inhibition markedly reduces inflammation and promotes bone repair in murine models. Further in vitro investigations into the regulatory mechanisms of HMGB1 in macrophages reveal its role in increasing Yes-associated protein (YAP) activity, which contributes to pro-inflammatory polarization. Additionally, conditioned media derived from macrophages influenced by HMGB1 significantly impair the migratory and osteogenic capabilities of bone marrow-derived mesenchymal stem cells, which are essential for bone regeneration. In vivo experiments further validate that the administration of exogenous HMGB1 exacerbates postoperative acute inflammation and obstructs osseointegration. The study concludes that inhibiting HMGB1 fosters an anti-inflammatory polarization of macrophages, leading to diminished postoperative acute inflammation and expedited osseointegration around dental implants in mice.

Fabrication and evaluation of Zn-EGCG-loaded chitosan scaffolds for bone regeneration: From cellular responses to in vivo performance

Fabrication and evaluation of Zn-EGCG-loaded chitosan scaffolds for bone regeneration: From cellular responses to in vivo performance

A Novel Triad of Bio-Inspired Design, Digital Fabrication, and Bio-Derived Materials for Personalised Bone Repair.

The emerging paradigm of personalised bone repair embodies a transformative triad comprising bio-inspired design, digital fabrication, and the exploration of innovative materials. The increasing average age of the population, alongside the rising incidence of fractures associated with age-related conditions such as osteoporosis, necessitates the development of customised, efficient, and minimally invasive treatment modalities as alternatives to conventional methods (e.g., autografts, allografts, Ilizarov distraction, and bone fixators) typically employed to promote bone regeneration. A promising innovative technique involves the use of cellularised scaffolds incorporating mesenchymal stem cells (MSCs). The selection of materials-ranging from metals and ceramics to synthetic or natural bio-derived polymers-combined with a design inspired by natural sources (including bone, corals, algae, shells, silk, and plants) facilitates the replication of geometries, architectures, porosities, biodegradation capabilities, and mechanical properties conducive to physiological bone regeneration. To mimic internal structures and geometries for construct customisation, scaffolds can be designed using Computer-aided Design (CAD) and fabricated via 3D-printing techniques. This approach not only enables precise control over external shapes and internal architectures but also accommodates the use of diverse materials that improve biological performance and provide economic advantages. Finally, advanced numerical models are employed to simulate, analyse, and optimise the complex processes involved in personalised bone regeneration, with computational predictions validated against experimental data and in vivo studies to ascertain the model's ability to predict the recovery of bone shape and function.