MgSiO3 Fiber Membrane Scaffold with Triggered Drug Delivery for Osteosarcoma Synergetic Therapy and Bone Regeneration.

In this research, a novel MgSiO3 fiber membrane (MSFM) loaded with indocyanine green (ICG) and doxorubicin (DOX) was prepared. Because of MgSiO3's unique lamellar structure composed of a silicon-oxygen tetrahedron, magnesium ion (Mg2+) moves easily and can be further replaced with other cations. Therefore, because of the positively charged functional group of ICG, MSFM has a rather high drug loading for ICG. In addition, there is electrostatic attraction between DOX (a cationic drug) and ICG (an anionic drug). Hence, after loading ICG, more DOX can be adsorbed into MSFM because of electrostatic interaction. The ICG endows the MSFM outstanding photothermal therapy (PTT) performance, and DOX as a chemotherapeutic drug can restrain tumor growth. On the one hand, H+ exchanged with the positively charged DOX based on the MgSiO3 special lamellar structure. On the other hand, the thermal effect could break the electrostatic interaction between ICG and DOX. Based on the above two points, both tumor acidic microenvironment and photothermal effect can trigger DOX release. What's more, in vitro and in vivo antiosteosarcoma therapy evaluations displayed a superior synergetic PTT-chemotherapy anticancer treatment and excellent biocompatibility of DOX&ICG-MSFM. Finally, the MSFM was proven to greatly promote cell proliferation, differentiation, and bone regeneration performance in vitro and in vivo. Therefore, MSFM provides a creative perspective in the design of multifunctional scaffolds and shows promising applications in controlled drug delivery, antitumor performance, and osteogenesis.

Bone Morphogenetic Protein 7-Loaded Gelatin Methacrylate/Oxidized Sodium Alginate/Nano-Hydroxyapatite Composite Hydrogel for Bone Tissue Engineering.

Background: Bone tissue engineering (BTE) is a promising alternative to autologous bone grafting for the clinical treatment of bone defects, and inorganic/organic composite hydrogels as BTE scaffolds are a hot spot in current research. The construction of nano-hydroxyapatite/gelatin methacrylate/oxidized sodium alginate (nHAP/GelMA/OSA), abbreviated as HGO, composite hydrogels loaded with bone morphogenetic protein 7 (BMP7) will provide a suitable 3D microenvironment to promote cell aggregation, proliferation, and differentiation, thus facilitating bone repair and regeneration. Methods: Dually-crosslinked hydrogels were fabricated by combining GelMA and OSA, while HGO hydrogels were formulated by incorporating varying amounts of nHAP. The hydrogels were physically and chemically characterized followed by the assessment of their biocompatibility. BMP7-HGO (BHGO) hydrogels were fabricated by incorporating suitable concentrations of BMP7 into HGO hydrogels. The osteogenic potential of BHGO hydrogels was then validated through in vitro experiments and using rat femoral defect models. Results: The addition of nHAP significantly improved the physical properties of the hydrogel, and the composite hydrogel with 10% nHAP demonstrated the best overall performance among all groups. The selected concentration of HGO hydrogel served as a carrier for BMP7 loading and was evaluated for its osteogenic potential both in vivo and in vitro. The BHGO hydrogel demonstrated superior in vitro osteogenic induction and in vivo potential for repairing bone tissue compared to the outcomes observed in the blank control, BMP7, and HGO groups. Conclusion: Using hydrogel containing 10% HGO appears promising for bone tissue engineering scaffolds, especially when loaded with BMP7 to boost its osteogenic potential. However, further investigation is needed to optimize the GelMA, OSA, and nHAP ratios, along with the BMP7 concentration, to maximize the osteogenic potential.

Coaxial Electrospun Polycaprolactone/Gelatin Nanofiber Membrane Loaded with Salidroside and Cryptotanshinone Synergistically Promotes Vascularization and Osteogenesis.

Background: Salidroside (SAL) is the most effective component of Rhodiola rosea, a traditional Chinese medicine. Cryptotanshinone (CT) is the main fat-soluble extract of Salvia miltiorrhiza, exhibiting considerable potential for application in osteogenesis. Herein, a polycaprolactone/gelatin nanofiber membrane loaded with CT and SAL (PSGC membrane) was successfully fabricated via coaxial electrospinning and characterized. Methods and Results: This membrane capable of sustained and controlled drug release was employed in this study. Co-culturing the membrane with bone marrow mesenchymal stem cells and human umbilical vein endothelial cells revealed excellent biocompatibility and demonstrated osteogenic and angiogenic capabilities. Furthermore, drug release from the PSGC membrane activated the Wnt/ß-catenin signaling pathway and promoted osteogenic differentiation and vascularization. Evaluation of the membrane's vascularization and osteogenic capacities involved transplantation onto a rat's subcutaneous area and assessing rat cranium defects for bone regeneration, respectively. Microcomputed tomography, histological tests, immunohistochemistry, and immunofluorescence staining confirmed the membrane's outstanding angiogenic capacity two weeks post-operation, with a higher incidence of osteogenesis observed in rat cranial defects eight weeks post-surgery. Conclusion: Overall, the SAL- and CT-loaded coaxial electrospun nanofiber membrane synergistically enhances bone repair and regeneration.

The efficacy of Platelet and Leukocyte Rich Fibrin (L-PRF) in the healing process and bone repair in oral and maxillofacial surgeries: a systematic review.

INTRODUCTION: The search to optimize the healing and bone repair processes in oral and maxillofacial surgeries reflects the constant evolution in clinical practice, driven by the demand for increasingly satisfactory results and the need to minimize postoperative complications. OBJECTIVE: To evaluate the efficacy of Platelet and Leukocyte Rich Fibrin (L-PRF) in the healing and bone repair process in oral and maxillofacial surgeries. MATERIALS AND METHODS: The systematic review protocol for this study included the definition of the research question, the domain of the study, the databases searched, the search strategy, the inclusion and exclusion criteria, the types of studies to be included, the measures of effect, the methods for screening, data extraction and analysis, and the approach to data synthesis. Systematic literature searches were carried out on Cochrane databases, Web of Science, PubMed, ScienceDirect, Embase and Google Scholar. RESULTS: The strategic search in the databases identified 1,159 studies. After removing the duplicates with the Rayyan© software, 946 articles remained. Of these, 30 met the inclusion criteria. After careful evaluation based on the inclusion and exclusion criteria, 8 studies were considered highly relevant and included in the systematic review. CONCLUSION: Platelet and Leukocyte Rich Fibrin (L-PRF) has a positive effect on the healing process and bone repair in oral and maxillofacial surgeries.

pH-Responsive Mesoporous Silica Nanoparticles Loaded with Naringin for Targeted Osteoclast Inhibition and Bone Regeneration.

Background: It is well-established that osteoclast activity is significantly influenced by fluctuations in intracellular pH. Consequently, a pH-sensitive gated nano-drug delivery system represents a promising therapeutic approach to mitigate osteoclast overactivity. Our prior research indicated that naringin, a natural flavonoid, effectively mitigates osteoclast activity. However, naringin showed low oral availability and short half-life, which hinders its clinical application. We developed a drug delivery system wherein chitosan, as gatekeepers, coats mesoporous silica nanoparticles loaded with naringin (CS@MSNs-Naringin). However, the inhibitory effects of CS@MSNs-Naringin on osteoclasts and the underlying mechanisms remain unclear, warranting further research. Methods: First, we synthesized CS@MSNs-Naringin and conducted a comprehensive characterization. We also measured drug release rates in a pH gradient solution and verified its biosafety. Subsequently, we investigated the impact of CS@MSNs-Naringin on osteoclasts induced by bone marrow-derived macrophages, focusing on differentiation and bone resorption activity while exploring potential mechanisms. Finally, we established a rat model of bilateral critical-sized calvarial bone defects, in which CS@MSNs-Naringin was dispersed in GelMA hydrogel to achieve in situ drug delivery. We observed the ability of CS@MSNs-Naringin to promote bone regeneration and inhibit osteoclast activity in vivo. Results: CS@MSNs-Naringin exhibited high uniformity and dispersity, low cytotoxicity (concentration≤120 µg/mL), and significant pH sensitivity. In vitro, compared to Naringin and MSNs-Naringin, CS@MSNs-Naringin more effectively inhibited the formation and bone resorption activity of osteoclasts. This effect was accompanied by decreased phosphorylation of key factors in the NF-κB and MAPK signaling pathways, increased apoptosis levels, and a subsequent reduction in the production of osteoclast-specific genes and proteins. In vivo, CS@MSNs-Naringin outperformed Naringin and MSNs-Naringin, promoting new bone formation while inhibiting osteoclast activity to a greater extent. Conclusion: Our research suggested that CS@MSNs-Naringin exhibited the strikingly ability to anti-osteoclasts in vitro and in vivo, moreover promoted bone regeneration in the calvarial bone defect.

An injectable magnesium-loaded hydrogel releases hydrogen to promote osteoporotic bone repair via ROS scavenging and immunomodulation.

Background: The repair of osteoporotic bone defects remains challenging due to excessive reactive oxygen species (ROS), persistent inflammation, and an imbalance between osteogenesis and osteoclastogenesis. Methods: Here, an injectable H2-releasing hydrogel (magnesium@polyethylene glycol-poly(lactic-co-glycolic acid), Mg@PEG-PLGA) was developed to remodel the challenging bone environment and accelerate the repair of osteoporotic bone defects. Results: This Mg@PEG-PLGA gel shows excellent injectability, shape adaptability, and phase-transition ability, can fill irregular bone defect areas via minimally invasive injection, and can transform into a porous scaffold in situ to provide mechanical support. With the appropriate release of H2 and magnesium ions, the 2Mg@PEG-PLGA gel (loaded with 2 mg of Mg) displayed significant immunomodulatory effects through reducing intracellular ROS, guiding macrophage polarization toward the M2 phenotype, and inhibiting the IκB/NF-κB signaling pathway. Moreover, in vitro experiments showed that the 2Mg@PEG-PLGA gel inhibited osteoclastogenesis while promoting osteogenesis. Most notably, in animal experiments, the 2Mg@PEG-PLGA gel significantly promoted the repair of osteoporotic bone defects in vivo by scavenging ROS and inhibiting inflammation and osteoclastogenesis. Conclusions: Overall, our study provides critical insight into the design and development of H2-releasing magnesium-based hydrogels as potential implants for repairing osteoporotic bone defects.

Epimedium-Curculigo herb pair enhances bone repair with infected bone defects and regulates osteoblasts through LncRNA MALAT1/miR-34a-5p/SMAD2 axis.

Infected bone defects (IBDs) are the common condition in the clinical practice of orthopaedics. Although surgery and anti-infective medicine are the firstly chosen treatments, in many cases, patients experience a prolonged bone union process after anti-infective treatment. Epimedium-Curculigo herb pair (ECP) has been proved to be effective for bone repair. However, the mechanisms of ECP in IBDs are insufficiency. In this study, Effect of ECP in IBDs was verified by micro-CT and histological examination. Qualitative and quantitative analysis of the main components in ECP containing medicated serum (ECP-CS) were performed. The network pharmacological approaches were then applied to predict potential pathways for ECP associated with bone repair. In addition, the mechanism of ECP regulating LncRNA MALAT1/miRNA-34a-5p/SMAD2 signalling axis was evaluated by molecular biology experiments. In vivo experiments indicated that ECP could significantly promote bone repair. The results of the chemical components analysis and the pathway identification revealed that TGF-ß signalling pathway was related to ECP. The results of in vitro experiments indicated that ECP-CS could reverse the damage caused by LPS through inhibiting the expressions of LncRNA MALAT1 and SMAD2, and improving the expressions of miR-34a-5p, ALP, RUNX2 and Collagen type І in osteoblasts significantly. This research showed that ECP could regulate the TGF-ß/SMADs signalling pathway to promote bone repair. Meanwhile, ECP could alleviate LPS-induced bone loss by modulating the signalling axis of LncRNA MALAT1/miRNA-34a-5p/ SMAD2 in IBDs.

Nanofibrous Microspheres: A Biomimetic Platform for Bone Tissue Regeneration.

Bone, a fundamental constituent of the human body, is a vital scaffold for support, protection, and locomotion, underscoring its pivotal role in maintaining skeletal integrity and overall functionality. However, factors such as trauma, disease, or aging can compromise bone structure, necessitating effective strategies for regeneration. Traditional approaches often lack biomimetic environments conducive to efficient tissue repair. Nanofibrous microspheres (NFMS) present a promising biomimetic platform for bone regeneration by mimicking the native extracellular matrix architecture. Through optimized fabrication techniques and the incorporation of active biomolecular components, NFMS can precisely replicate the nanostructure and biochemical cues essential for osteogenesis promotion. Furthermore, NFMS exhibit versatile properties, including tunable morphology, mechanical strength, and controlled release kinetics, augmenting their suitability for tailored bone tissue engineering applications. NFMS enhance cell recruitment, attachment, and proliferation, while promoting osteogenic differentiation and mineralization, thereby accelerating bone healing. This review highlights the pivotal role of NFMS in bone tissue engineering, elucidating their design principles and key attributes. By examining recent preclinical applications, we assess their current clinical status and discuss critical considerations for potential clinical translation. This review offers crucial insights for researchers at the intersection of biomaterials and tissue engineering, highlighting developments in this expanding field.

3D Printed Calcium Phosphate Physiochemically Dual-Regulating Pro-Osteogenesis and Antiosteolysis for Enhancing Bone Tissue Regeneration.

Osteoblasts and osteoclasts are two of the most important types of cells in bone repair, and their bone-forming and bone-resorbing activities influence the process of bone repair. In this study, we proposed a physicochemical bidirectional regulation strategy via ration by physically utilizing hydroxyapatite nanopatterning to recruit and induce MSCs osteogenic differentiation and by chemically inhibiting osteolysis activity through the loaded zoledronate. The nanorod-like hydroxyapatite coating was fabricated via a modified hydrothermal process while the zoledronic acid was loaded through the chelation within the calcium ions. The fabrication of a hydroxyapatite/zoledronic acid composite biomaterial. This biomaterial promotes bone tissue regeneration by physically utilizing hydroxyapatite nanopatterning to recruit and induce MSCs osteogenic differentiation and by chemically inhibiting osteolysis activity through the loaded zoledronate. The nanorod-like hydroxyapatite coating was fabricated via a modified hydrothermal process while the zoledronic acid was loaded through the chelation within the calcium ions. The in vitro results tested on MSCs and RAW 246.7 indicated that the hydroxyapatite enhanced cells' physical sensing system, therefore enhancing the osteogenesis. At the same time the zoledronic acid inhibited osteolysis by downregulating the RANK-related genes. This research provides a promising strategy for enhancing bone regeneration and contributes to the field of orthopedic implants.

Yoda1 pretreated BMSC derived exosomes accelerate osteogenesis by activating phospho-ErK signaling via Yoda1-mediated signal transmission.

Segmental bone defects, arising from factors such as trauma, tumor resection, and congenital malformations, present significant clinical challenges that often necessitate complex reconstruction strategies. Hydrogels loaded with multiple osteogenesis-promoting components have emerged as promising tools for bone defect repair. While the osteogenic potential of the Piezo1 agonist Yoda1 has been demonstrated previously, its hydrophobic nature poses challenges for effective loading onto hydrogel matrices.In this study, we address this challenge by employing Yoda1-pretreated bone marrow-derived mesenchymal stem cell (BMSCs) exosomes (Exo-Yoda1) alongside exosomes derived from BMSCs (Exo-MSC). Comparatively, Exo-Yoda1-treated BMSCs exhibited enhanced osteogenic capabilities compared to both control groups and Exo-MSC-treated counterparts. Notably, Exo-Yoda1-treated cells demonstrated similar functionality to Yoda1 itself. Transcriptome analysis revealed activation of osteogenesis-associated signaling pathways, indicating the potential transduction of Yoda1-mediated signals such as ErK, a finding validated in this study. Furthermore, we successfully integrated Exo-Yoda1 into gelatin methacryloyl (GelMA)/methacrylated sodium alginate (SAMA)/ß-tricalcium phosphate (ß-TCP) hydrogels. These Exo-Yoda1-loaded hydrogels demonstrated augmented osteogenesis in subcutaneous ectopic osteogenesis nude mice models and in rat skull bone defect model. In conclusion, our study introduces Exo-Yoda1-loaded GELMA/SAMA/ß-TCP hydrogels as a promising approach to promoting osteogenesis. This innovative strategy holds significant promise for future widespread clinical applications in the realm of bone defect reconstruction.

Bioinspired soft-hard combined system with mild photothermal therapeutic activity promotes diabetic bone defect healing via synergetic effects of immune activation and angiogenesis.

Background: The comprehensive management of diabetic bone defects remains a substantial clinical challenge due to the hostile regenerative microenvironment characterized by aggravated inflammation, excessive reactive oxygen species (ROS), bacterial infection, impaired angiogenesis, and unbalanced bone homeostasis. Thus, an advanced multifunctional therapeutic platform capable of simultaneously achieving immune regulation, bacterial elimination, and tissue regeneration is urgently designed for augmented bone regeneration under diabetic pathological milieu. Methods and Results: Herein, a photoactivated soft-hard combined scaffold system (PGCZ) was engineered by introducing polydopamine-modified zeolitic imidazolate framework-8-loaded double-network hydrogel (soft matrix component) into 3D-printed poly(ε-caprolactone) (PCL) scaffold (hard matrix component). The versatile PGCZ scaffold based on double-network hydrogel and 3D-printed PCL was thus prepared and features highly extracellular matrix-mimicking microstructure, suitable biodegradability and mechanical properties, and excellent photothermal performance, allowing long-term structural stability and mechanical support for bone regeneration. Under periodic near-infrared (NIR) irradiation, the localized photothermal effect of PGCZ triggers the on-demand release of Zn2+, which, together with repeated mild hyperthermia, collectively accelerates the proliferation and osteogenic differentiation of preosteoblasts and potently inhibits bacterial growth and biofilm formation. Additionally, the photoactivated PGCZ system also presents outstanding immunomodulatory and ROS scavenging capacities, which regulate M2 polarization of macrophages and drive functional cytokine secretion, thus leading to a pro-regenerative microenvironment in situ with enhanced vascularization. In vivo experiments further demonstrated that the PGCZ platform in conjunction with mild photothermal therapeutic activity remarkably attenuated the local inflammatory cascade, initiated endogenous stem cell recruitment and neovascularization, and orchestrated the osteoblast/osteoclast balance, ultimately accelerating diabetic bone regeneration. Conclusions: This work highlights the potential application of a photoactivated soft-hard combined system that provides long-term biophysical (mild photothermal stimulation) and biochemical (on-demand ion delivery) cues for accelerated healing of diabetic bone defects.

Influence of zoledronic acid and low-intensity laser on collagen fibers during the bone repair process.

PURPOSE: To evaluate collagen fibers during the bone repair process in critical defects created in the tibias of rats, treated with zoledronic acid (AZ) associated with low-level laser therapy (LLLT). METHODS: Ten rats were distributed according to treatment: group 1) saline solution; group 2) LLLT; group 3) AZ; group 4) AZ and LLLT. AZ was administered at the dose of 0.035 mg/kg at fortnightly intervals over eight weeks. Next, 2-mm bone defects were created in the tibias of all animals. The bone defects in groups 2 and 4 were irradiated LLLT in the immediate postoperative period. After periods 14 and 28 of application, the animals were euthanized, and birefringence analysis was performed. RESULTS: Approximately 90% of the total area was occupied by collagen fibers within the red color spectrum, this area being statistically larger in relation to the area occupied by collagen fibers within the green and yellow spectrum, in the four groups. Over the 14-day period, there was no statistically significant difference between the groups. In the 28-day period, group 2 (14.02 ± 15.9%) was superior in quantifying green birefringent fibers compared to group 1 (3.06 ± 3.24%), with p = 0.009. CONCLUSIONS: LLLT associated with ZA is effective in stimulating the neoformation of collagen fibers. The LLLT group without the association with ZA showed a greater amount of immature and less organized matrix over a period of 28 days.

A comprehensive in vitro characterization of non-crosslinked, diverse tissue-derived collagen-based membranes intended for assisting bone regeneration.

Collagen-based membranes are class III-medical devices widely used in dental surgical procedures to favour bone regeneration. Here, we aimed to provide biophysical and biochemical data on this type of devices to support their optimal use and design/manufacturing. To the purpose, four commercial, non-crosslinked collagen-based-membranes, obtained from various sources (equine tendon, pericardium or cortical bone tissues, and porcine skin), were characterized in vitro. The main chemical, biophysical and biochemical properties, that have significant clinical implications, were evaluated. Membranes showed similar chemical features. They greatly differed in morphology as well as in porosity and density and showed a diverse ranking in relation to these latter two parameters. Samples highly hydrated in physiological medium (swelling-ratio values in the 2.5-6.0 range) and, for some membranes, an anisotropic expansion during hydration was, for the first time, highlighted. Rheological analyses revealed great differences in deformability (150-1500kPa G') also alerting about the marked variation in membrane mechanical behaviour upon hydration. Samples proved diverse sensitivity to collagenase, with the cortical-derived membrane showing the highest stability. Biological studies, using human-bone-derived cells, supported sample ability to allow cell proliferation and to prompt bone regeneration, while no relevant differences among membranes were recorded. Prediction of relative performance based on the findings was discussed. Overall, results represent a first wide panel of chemical/biophysical/biochemical data on collagen-based-membranes that 1) enhances our knowledge of these products, 2) aids their optimal use by providing clinicians with scientific basis for selecting products based on the specific clinical situation and 3) represents a valuable reference for optimizing their manufacturing.

Eggshell membrane as a regenerative material in alveolar bone grafting in combination with advanced platelet rich fibrin.

Abstract: The eggshell and the eggshell membrane (ESM) are significant by-products of the poultry industry and are being utilized for various valuable purposes in health care, like soft tissue healing and pain alleviation. The aim and objective of our study are to assess the effect of the eggshell membrane on alveolar bone regeneration after tooth extraction. A total of 40 extraction sockets (bilateral) among 20 patients were assessed clinically for healing, and radiographic parameters of bone density and socket volume were assessed on CBCT at baseline, 3 months, and 6 months. Advanced platelet-rich fibrin was created from 5 ml of autologous blood from the patient and centrifuged for 15 minutes at 1500 RPM/168 RCF. The commercially available powdered form of egg shell membrane was used in the study. Based on the randomized allotment (coin-flip), A-PRF alone or A-PRF mixed with eggshell membrane was placed inside the extraction socket and was stabilized using 3-0 silk sutures. It was ob-served that wound healing was uneventful in all 20 patients. No evidence of dry sockets or allergic reactions was noted in any patient. Statistical analysis was done using the un-paired t-test and Mann-Whitney U test with SPSS version 20.0. P<0.05 was considered significant. On comparison of the mean bone density at baseline, 3 months, and 6 months, the socket density in the eggshell with the PRF group was higher compared to the control group. To conclude, eggshell membrane has good regenerative properties and excellent osteogenic capacity; therefore, it could be a useful graft due to its low cost, abundant availability, and simple application.

Humidity-Responsive Amorphous Calcium-Magnesium Pyrophosphate/Cassava Starch Scaffold for Enhanced Neurovascular Bone Regeneration.

Developing a neurovascular bone repair scaffold with an appropriate mechanical strength remains a challenge. Calcium phosphate (CaP) is similar to human bone, but its scaffolds are inherently brittle and inactive, which require recombination with active ions and polymers for bioactivity and suitable strength. This work discussed the synthesis of amorphous magnesium-calcium pyrophosphate (AMCP) and the subsequent development of a humidity-responsive AMCP/cassava starch (CS) scaffold. The scaffold demonstrated enhanced mechanical properties by strengthening the intermolecular hydrogen bonds and ionic bonds between AMCP and CS during the gelatinization and freeze-thawing processes. The release of active ions was rapid initially and stabilized into a long-term stable release after 3 days, which is well-matched with new bone growth. The release of pyrophosphate ions endowed the scaffold with antibacterial properties. At the cellular level, the released active ions simultaneously promoted the proliferation and mineralization of osteoblasts, the proliferation and migration of endothelial cells, and the proliferation of Schwann cells. At the animal level, the scaffold was demonstrated to promote vascular growth and peripheral nerve regeneration in a rat skull defect experiment, ultimately resulting in the significant and rapid repair of bone defects. The construction of the AMCP/CS scaffold offers practical suggestions and references for neurovascular bone repair.

Exploring the biocompatibility and healing activity of actinobacterial-enhanced reduced nano-graphene oxide in in vitro and in vivo model and induce bone regeneration through modulation of OPG/RANKL/RUNX2/ALP pathways.

BACKGROUND: The development of cost-effective, simple, environment-friendly biographene is an area of interest. To accomplish environmentally safe, benign culturing that has advantages over other methods to reduce the graphene oxide (GO), extracellular metabolites from actinobacteria associated with mushrooms were used for the first time. METHODS: Bactericidal effect of GO against methicillin-resistant Staphylococcus aureus, antioxidant activity, and hydroxyapatite-like bone layer formation, gene expression analysis and appropriate biodegradation of the microbe-mediated synthesis of graphene was studied. RESULTS: Isolated extracellular contents Streptomyces achromogenes sub sp rubradiris reduced nano-GO to graphene (rGO), which was further examined by spectrometry and suggested an efficient conversion and significant reduction in the intensity of all oxygen-containing moieties and shifted crystalline peaks. Electron microscopic results also suggested the reduction of GO layer. In addition, absence of significant toxicity in MG-63 cell line, intentional free radical scavenging prowess, liver and kidney histopathology, and Wistar rat bone regeneration through modulation of OPG/RANKL/RUNX2/ALP pathways show the feasibility of the prepared nano GO. CONCLUSIONS: The study demonstrates the successful synthesis of biographene from actinobacterial extracellular metabolites, its potential biomedical applications, and its promising role in addressing health and environmental concerns.

Enhancing bone regeneration and immunomodulation via gelatin methacryloyl hydrogel-encapsulated exosomes from osteogenic pre-differentiated mesenchymal stem cells.

Mesenchymal stem cell-derived exosomes (MSC-Exos) have emerged as promising candidates for cell-free therapy in tissue regeneration. However, the native osteogenic and angiogenic capacities of MSC-Exos are often insufficient to repair critical-sized bone defects, and the underlying immune mechanisms remain elusive. Furthermore, achieving sustained delivery and stable activity of MSC-Exos at the defect site is essential for optimal therapeutic outcomes. Here, we extracted exosomes from osteogenically pre-differentiated human bone marrow mesenchymal stem cells (hBMSCs) by ultracentrifugation and encapsulated them in gelatin methacryloyl (GelMA) hydrogel to construct a composite scaffold. The resulting exosome-encapsulated hydrogel exhibited excellent mechanical properties and biocompatibility, facilitating sustained delivery of MSC-Exos. Osteogenic pre-differentiation significantly enhanced the osteogenic and angiogenic properties of MSC-Exos, promoting osteogenic differentiation of hBMSCs and angiogenesis of human umbilical vein endothelial cells (HUVECs). Furthermore, MSC-Exos induced polarization of Raw264.7 cells from a pro-inflammatory phenotype to an anti-inflammatory phenotype under simulated inflammatory conditions, thereby creating an immune microenvironment conducive to osteogenesis. RNA sequencing and bioinformatics analysis revealed that MSC-Exos activate the p53 pathway through targeted delivery of internal microRNAs and regulate macrophage polarization by reducing DNA oxidative damage. Our study highlights the potential of osteogenic exosome-encapsulated composite hydrogels for the development of cell-free scaffolds in bone tissue engineering.

Mg-Cross-Linked Alginate Hydrogel Induces BMSC/Macrophage Crosstalk to Enhance Bone Tissue Regeneration via Dual Promotion of the Ligand-Receptor Pairing of the OSM/miR-370-3p-gp130 Signaling Pathway.

Macrophages play a pivotal role in the crosstalk between the immune and skeletal systems, while Mg-based biomaterials demonstrate immunomodulatory capabilities in this procedure. However, the mechanism of how Mg2+ promotes osteogenesis through the interplay of bone marrow-derived mesenchymal stem cells (BMSCs) and macrophages remains undescribed. Here, we demonstrated that a Mg-cross-linked alginate hydrogel exerted a dual enhancement of BMSCs osteogenic differentiation through the ligand-receptor pairing of the OSM/miR-370-3p-gp130 axis. On the one hand, Mg2+, released from the Mg-cross-linked hydrogel, stimulates bone marrow-derived macrophages to produce and secrete more OSM. On the other hand, Mg2+ lowers the miR-370-3p level in BMSCs and in turn, reverses its suppression on gp130. Then, the OSM binds to the gp130 heterodimer receptor and activates intracellular osteogenic programs in BMSCs. Taken together, this study reveals a novel cross-talk pattern between the skeletal and immune systems under Mg2+ stimulation. This study not only brings new insights into the immunomodulatory properties of Mg-based biomaterials for orthopedic applications but also enriches the miRNA regulatory network and provides a promising target to facilitate bone regeneration in large bone defects.

From bone to nanoparticles: development of a novel generation of bone derived nanoparticles for image guided orthopedic regeneration.

Bone related diseases such as osteoporosis, osteoarthritis, metastatic bone cancer, osteogenesis imperfecta, and Paget's disease, are primarily treated with pharmacologic therapies that often exhibit limited efficacy and substantial side effects. Bone injuries or fractures are primarily repaired with biocompatible materials that produce mixed results in sufficiently regenerating healthy and homogenous bone tissue. Each of these bone conditions, both localized and systemic, use different strategies with the same goal of achieving a healthy and homeostatic bone environment. In this study, we developed a new type of bone-based nanoparticle (BPs) using the entire organic extracellular matrix (ECM) of decellularized porcine bone, additionally encapsulating indocyanine green dye (ICG) for an in vivo monitoring capability. Utilizing the regenerative capability of bone ECM and the functionality of nanoparticles, the ICG encapsulated BPs (ICG/BPs) have been demonstrated to be utilized as a therapeutic option for localized and systemic orthopedic conditions. Additionally, ICG enables an in situ monitoring capability in the Short-Wave Infrared (SWIR) spectrum, capturing the degradation or the biodistribution of the ICG/BPs after both local implantation and intravenous administration, respectively. The efficacy and safety of the ICG/BPs shown within this study lay the foundation for future investigations, which will delve into optimization for clinical translation.

MgCa-Based Alloys Modified with Zn- and Ga-Doped CaP Coatings Lead to Controlled Degradation and Enhanced Bone Formation in a Sheep Cranium Defect Model.

Mg-based biodegradable metallic implants are gaining increased attraction for applications in orthopedics and dentistry. However, their current applications are hampered by their high rate of corrosion, degradation, and rapid release of ions and gas bubbles into the physiological medium. The aim of the present study is to investigate the osteogenic and angiogenic potential of coated Mg-based implants in a sheep cranial defect model. Although their osteogenic potential was studied to some extent, their potential to regenerate vascularized bone formation was not studied in detail. We have studied the potential of magnesium-calcium (MgCa)-based alloys modified with zinc (Zn)- or gallium (Ga)-doped calcium phosphate (CaP) coatings as a strategy to control their degradation rate while enhancing bone regeneration capacity. MgCa and its implants with CaP coatings (MgCa/CaP) as undoped or as doped with Zn or Ga (MgCa/CaP + Zn and MgCa/CaP + Ga, respectively) were implanted in bone defects created in the sheep cranium. MgCa implants degraded faster than the others at 4 weeks postop and the weight loss was ca. 50%, while it was ca. 15% for MgCa/CaP and <10% in the presence of Zn and Ga with CaP coating. Scanning electron microscopy (SEM) analysis of the implant surfaces also revealed that the MgCa implants had the largest degree of structural breakdown of all the groups. Radiological evaluation revealed that surface modification with CaP to the MgCa implants induced better bone regeneration within the defects as well as the enhancement of bone-implant surface integration. Bone volume (%) within the defect was ca. 25% in the case of MgCa/CaP + Ga, while it was around 15% for undoped MgCa group upon micro-CT evaluation. This >1.5-fold increase in bone regeneration for MgCa/CaP + Ga implant was also observed in the histopathological examination of the H&E- and Masson's trichrome-stained sections. Immunohistochemical analysis of the bone regeneration (antiosteopontin) and neovascularization (anti-CD31) at the defect sites revealed >2-fold increase in the expression of the markers in both Ga- and Zn-doped, CaP-coated implants. Zn-doped implants further presented low inflammatory reaction, notable bone regeneration, and neovascularization among all the implant groups. These findings indicated that Ga- and Zn-doped CaP coating is an important strategy to control the degradation rate as well as to achieve enhanced bone regeneration capacity of the implants made of Mg-based alloys.