Osteogenic Differentiation Properties Research Articles

In vitro and in vivo studies of a biodegradable Zn-4Ag-0.1Sc alloy with high strength-elongation product, cytocompatibility, osteogenic differentiation, and anti-infection properties for guided bone-regeneration membrane applications

Zinc-silver (Zn-Ag) alloys are generally promising guided bone-regeneration membrane (GBRM) materials due to their moderate degradability, osteogenic differentiation, and antibacterial properties. However, Zn-Ag alloys often display microstructural inhomogeneity and mechanical instability due to the formation of coarse Ag-rich second phases. In this study, Zn-4Ag and Zn-4Ag-0.1Sc (denoted ZA and ZAS, respectively) were comparatively investigated, and the ZAS exhibited a suitable degradation rate, high strength-elongation product, cytocompatibility, antibacterial capacity, and in vitro and in vivo osteogenic properties, making it highly appropriate for GBRM applications. Among all the as-cast and hot-rolled (HR) samples, the HR ZAS had the highest ultimate tensile strength of ∼260.5 MPa, tensile yield strength of ∼202.0 MPa, and elongation of ∼72.7%. The HR ZAS also exhibited a higher degradation rate of ∼36.5 µm/a in Hanks’ solution than those of the HR ZA, while its diluted extract was more cytocompatible and capable of osteogenic differentiation toward both MG-63 and MC3T3-E1 cells. The HR ZAS showed an exceptionally effective antibacterial ability against S. aureus in both in vitro antibacterial testing and in vivo subcutaneous infection models. Further, the HR ZAS demonstrated better osteogenic and histocompatibility properties than those of pure Zn in a rat skull defect model.

Tannic acid and quaternized chitosan mediated puerarin-loaded octacalcium phosphate /sodium alginate scaffold for bone tissue engineering

Current limitations in mechanical performance and foreign body reactions (FBR) often lead to implant failure, restricting the application of bioceramic scaffolds. This study presents a novel 3D-printed scaffold that combines the release of anti-inflammatory drugs with osteogenic stimulation. Initially, the inorganic and organic phases were integrated to ensure the scaffold's mechanical integrity through catechol chemistry and the electrostatic interactions between tannic acid and quaternary ammonium chitosan. Subsequently, layers of polydopamine-encapsulated puerarin-loaded zeolitic imidazolate framework-8 (ZIF-8) were self-assembled onto the stent's surface, creating the drug-loaded scaffold that improved drug release without altering the scaffold's structure. Compared with unloaded scaffolds, the puerarin-loaded scaffold demonstrated excellent osteogenic differentiation properties along with superior anti-inflammatory and osteogenic effects in a range of in vitro and in vivo studies. RNA sequencing clarified the role of the TNF and NF/κB signaling pathways in these effects, further supporting the scaffold's osteogenic potential. This study introduces a novel approach for creating drug-loaded scaffolds, providing a unique method for treating cancellous bone defects.

Osteogenic potential of adipose stem cells on hydroxyapatite-functionalized decellularized amniotic membrane

Amniotic membrane (AM) is an attractive source for bone tissue engineering because of its low immunogenicity, contains biomolecules and proteins, and osteogenic differentiation properties. Hydroxyapatite is widely used as bone scaffolds due to its biocompatibility and bioactivity properties. The aim of this study is to design and fabricate scaffold based on hydroxyapatite-coated decellularized amniotic membrane (DAM-HA) for bone tissue engineering purpose. So human amniotic membranes were collected from healthy donors and decellularized (DAM). Then a hydroxyapatite-coating was created by immersion in 10X SBF, under variable parameters of pH and incubation time. Hydroxyapatite-coating was characterized and the optimal sample was selected. Human adipose-derived mesenchymal stem cell behaviors were assessed on control, amniotic membrane, and coated amniotic membrane. The results of the SEM, MTT assay, and Live-Dead staining showed that DAM and DAM-HA support cell adhesion, viability and proliferation. Osteogenic differentiation was evaluated by assessment of alkaline phosphatase activity and expression of osteogenic markers. Maximum gene expression values compared to control occurred in 14 days for alkalin phosphatase, while the highest values for osteocalcin and osteopontin in 21 days. These gene expression values in DAM and DAM-HA for alkalin phosphatase is 6.41 and 8.47, for osteocalcin is 3.95 and 5.94 and for osteopontin is 5.59 and 9.9 respectively. The results of this study indicated DAM supports the survival and growth of stem cells. Also, addition of hydroxyapatite component to DAM promotes osteogenic differentiation while maintaining viability. Therefore, hydroxyapatite-coated decellularized amniotic membrane can be a promising choice for bone tissue engineering applications.

Effectiveness of autologous growth factor concentrates combined with topical minoxidil in patients of androgenic alopecia

Abstract Background: Concentrated growth factor (CGF) is a form of platelet concentrate. CGF contains abundant autologous growth factors that can promote cell proliferation, migration, osteogenic differentiation, and angiogenic properties in wound healing and bone regeneration. Recent studies revealed that CGF injection in hairless scalp could enhance hair density and optimize hair growth in androgenic alopecia (AGA) patients. Objective: The objective of this study was to study the effectiveness of autologous growth factor concentrate (GFC) combined with topical minoxidil in patients of AGA. Materials and Methods: A prospective nonrandomized interventional study with before and after comparison was carried out among 22 patients diagnosed with AGA. They were treated with deep intradermal injections of GFC in scalp. Four injections were administered 4 weeks apart, and patients were followed for 16 weeks. Treatment outcomes were assessed by taking photographs, using Global Aesthetic Improvement Scale (GAIS), and by performing a hair pull test after 16 weeks of therapy and compared to baseline. Incidence of adverse events was recorded. Patient’s self-satisfaction was assessed using a survey-based questionnaire at the end of the study. Results: Global macroscopic photographs showed a significant improvement in hair growth post-GFC therapy in all 22 patients. GAIS suggested that GFC treatments were effective in treating AGA, and the majority of patients were satisfied with their improvement. Hair pull test was negative in 100% of patients 4 months posttherapy. Therapy was found to be well tolerated with high patient satisfaction (100%). In addition, treatments resulted in a faster rate of hair growth and a decrease in greasy and unpleasant sensation of hair. Conclusion: GFC was found to have a promising role in the management of AGA in both males and females.

Stimulation of Bone ingrowth using YSZ/ β-TCP/PCL composite bilayer coating on 316 LSS scaffold for orthopedic application

The demand towards ideal tissue construct using polymer and ceramics made the researchers to do the search of polymer composites with desirable properties. Material selection for the composite play a major role to get long life. The selection of materials can be based on the nature, location and tissue type, which should be regenerated. Normally, a bone construct has its own requirements like osteo conduction properties, Tendency to mineralize, Rate of degradation and osteogenic differentiation properties. The best approach is to create regenerative medicine using suitable devices. This work focuses on developing the scaffold using 316L stainless steel fabricated with dual coating. The first layer of coating was made using Yttria Stabilized Zirconia by electrophoretic deposition. While the top second layer made as electro spun over 316L stainless steel . The electro spun made with β-Tricalcium phosphate (β-TCP) incorporated in PCL (Polycaprolactone). The process of electrospinning preferred to achieve porous surface. The bilayer scaffold performance was evaluated by surface morphology, bioactivity, bioresorbable and biodegradability with its cell adhesion capacity were studied. The results of X-ray diffraction reveal the presence of nanoparticle on the top layer of 316L stainless steel scaffold. The surface topography studies using Field Emission Scanning Electron Microscopy (FESEM) confirms more than 70 % porosity. The functional group present in YSZ/β-TCP/PCL composite bilayer on 316L SS were determined using FTIR. The developed bilayer coated 316L Stainless steel scaffolds further evaluated by invitro studies to confirm the cell adhesion capability. MG 63 cell line isolated from the bone and possess fibroblast morphology was used for the assay. The cells were cultured and exposed to the developed scaffold, the cultured cells were exposed to MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and the reduction of MTT directly measures the cell viability and the color change read through spectrophotometer. The cell growth and proliferation confirm its cell adhesion property. This present study helps in drug delivery using the nano fibers incorporated with bioresorbable TCP. The presence of TCP on the top of electro spun layer substantially supports the osteo conductivity through mineralization and degradation property.

Construction of oxidized icariin functionalized collagen composite with promoting osteogenesis, vascularization and anti-inflammatory properties potential for bone repair application

Bone defects are mainly treated by transplanting bone scaffold, and lack of osteogenesis, vascularization and anti-inflammatory properties will reduce the ability of new bone tissue to grow into them, thus increasing the risk of bone repair failure. In this study, inspired by the composition of natural bone, COL-BG-MOF composite was first prepared (collagen (COL) as the organic component, aminated mesoporous bioactive glass (BG-NH2) as the inorganic non-metallic component, and mesoporous silica shell-coated Mg-MOF-74 (Mg-MOF-74@MSiO2) as the metallic trace element component). Subsequently, in order to further enhance the effectiveness of its bone repair application potential, COL-BG-MOF was functionalized by oxidized Icariin (OICA) as a “growth factor” component to endow it with simultaneous osteogenesis promoting, vascularization promoting, and anti-inflammatory properties. Notably, the –CHO of OICA can react with the –NH2 in COL-BG-MOF by Schiff base reaction, which can cross-link the COL, thus improving the interfacial binding of BG-NH2 to the COL and slowing down the release rate of OICA. The results showed that the obtained functionalized composite scaffold exhibited better compressive strength, anti-degradation and osteoconductivity, as well as sustained OICA release behavior. More importantly, the synergistic effect of OICA and Mg-MOF-74@MSiO2 greatly promoted its osteogenic differentiation, HUVEC migration and anti-inflammatory properties. Therefore, this study provided a strategy to prepare functionalized composites by using modified Chinese medicine, which has great application potential in the field of bone regeneration.

Meticulously engineered three-dimensional-printed scaffold with microarchitecture and controlled peptide release for enhanced bone regeneration.

The repair of large load-bearing bone defects requires superior mechanical strength, a feat that a single hydrogel scaffold cannot achieve. The objective is to seamlessly integrate optimal microarchitecture, mechanical robustness, vascularisation, and osteoinductive biological responses to effectively address these critical load-bearing bone defects. To confront this challenge, three-dimensional (3D) printing technology was employed to prepare a polycaprolactone (PCL)-based integrated scaffold. Within the voids of 3D printed PCL scaffold, a methacrylate gelatin (GelMA)/methacrylated silk fibroin (SFMA) composite hydrogel incorporated with parathyroid hormone (PTH) peptide-loaded mesoporous silica nanoparticles (PTH@MSNs) was embedded, evolving into a porous PTH@MSNs/GelMA/SFMA/PCL (PM@GS/PCL) scaffold. The feasibility of fabricating this functional scaffold with a customised hierarchical structure was confirmed through meticulous chemical and physical characterisation. Compression testing unveiled an impressive strength of 17.81 ± 0.83 MPa for the composite scaffold. Additionally, in vitro angiogenesis potential of PM@GS/PCL scaffold was evaluated through Transwell and tube formation assays using human umbilical vein endothelium, revealing the superior cell migration and tube network formation. The alizarin red and alkaline phosphatase staining assays using bone marrow-derived mesenchymal stem cells clearly illustrated robust osteogenic differentiation properties within this scaffold. Furthermore, the bone repair potential of the scaffold was investigated on a rat femoral defect model using micro-computed tomography and histological examination, demonstrating enhanced osteogenic and angiogenic performance. This study presents a promising strategy for fabricating a microenvironment-matched composite scaffold for bone tissue engineering, providing a potential solution for effective bone defect repair.

Preparation and properties of porous calcium phosphate ceramic microspheres modified with magnesium phosphate surface coating for bone defect repair

Most studies have highlighted the critical influence of bioactive metal ions and pore structure on the bone repair performance of calcium phosphate. In this study, porous calcium phosphate ceramic microspheres with different porosities (45 %, 60 %, and 75 %) and pore sizes (20, 40, and 100 μm) were constructed by combining the extrusion-rolling and pore-forming agent methods, and they were then characterized as well as their physicochemical and biological properties. On this basis, the screened porous calcium phosphate microspheres were further coated with magnesium phosphate to improve the performance of osteogenesis and angiogenesis. The results demonstrated that pore size and porosity promoted the degradation properties. However, excessive pore size and porosity also resulted in a significant decline in the mechanical performance and biological properties of the microspheres. Successful magnesium phosphate coating of ceramic microspheres did not adversely affect their physicochemical performance and allowed stable release of magnesium ions, which further enhanced the biological properties of porous ceramic microspheres, such as cell proliferation, osteogenic differentiation, and angiogenic properties. This study presents an efficient and practical processing method to further enhance the properties and expand the applications of calcium phosphate materials.

Preparation of cerium-containing nanoporous titanium coatings for osseointegration and their promotion of osteogenic differentiation and anti-inflammatory properties

Conventional implants face many problems, such as failure to form good osseointegration and peri-implantitis in the early stage of implantation. It has been shown that hydroxyapatite (HA) has good osteoconductive ability. Also considering the potential of cerium oxide in osteogenesis and anti-inflammation, we prepared cerium-containing nanoporous HA coatings on the surface of pure titanium using the micro-arc oxidation (MAO) technique. The surface morphology of the coating was observed by scanning electron microscopy (SEM). The mechanical strength of the coating was examined by the ultrasonic oscillator. The elemental composition of the coating was examined by energy spectrum analysis (EDS). The ion release capacity of the cerium-containing coatings was examined by inductively coupled plasma emission spectrometry (ICP-OES). The hydrophilic properties of the coatings were examined by the hydrophilic angle test. In vitro, experiments were performed using rat bone marrow mesenchymal stem cells (BMSCs) and mouse mononuclear macrophages (Raw264.7). The biosafety of the cerium-containing coating was verified by live-dead staining and CCK-8 proliferation assay. The osteogenic and anti-inflammatory ability of the cerium-containing coating was examined by immunofluorescence staining and quantitative polymerase chain reaction (q-PCR). In addition, ion experiments were used to further demonstrate the osteogenic and anti-inflammatory potential of cerium ions. Subsequent animal experiments further demonstrated the osteoinductive potential of the cerium-containing HA coating. In conclusion, our cerium (HA)-containing coatings prepared by micro-arc oxidation on titanium surfaces show excellent osteogenic and anti-inflammatory properties, which are expected to improve the functionality of clinical implants and also lay the foundation for the clinical application of cerium ions.

4D Printing of Personalized-Tunable Biomimetic Periosteum with Anisotropic Microstructure for Accelerated Vascularization and Bone Healing.

An ideal biomimetic periosteum is expected to wrap various bone surfaces to orchestrate an optimal microenvironment for bone regeneration, including facilitating local vascularization, recruiting osteoblasts, and mineralizing the extracellular matrix (ECM). To mimic the role of the natural periosteum in promoting bone repair, a 4D printing technique to inlay aligned cell sheets on shape-shifting hydrogel is used, containing biophysical signals and spatially adjustable physical properties, for the first time. The outer hydrogel layer endows the biomimetic periosteum with the ability to digitally coordinate its 3D geometry to match the specific macroscopic bone shape to maintain a bone healing microenvironment. The inner aligned human mesenchymal stem cells (hMSCs) layer not only promotes the migration and angiogenesis of co-cultured cells but also exhibits excellent osteogenic differentiation properties. In vivo experiments show that apart from morphing preset shapes as physical barriers, the aligned biomimetic periosteum can actively facilitate local angiogenesis and early-stage osteogenesis. Altogether, this present work provides a novel route to construct a personalized biomimetic periosteum with anisotropic microstructure by introducing a tunable shape to maintain the bone reconstruction microenvironment and this strategy can be extended to repair sophisticated bone defects.

ZnO nanoparticles-modified polycaprolactone-gelatin membranes for guided/bone tissue regeneration, antibacterial and osteogenic differentiation properties

Periodontitis is a highly prevalent infectious disease that causes the progressive destruction of the periodontal supporting tissues. If left untreated, it can lead to tooth loss impairing oral function, aesthetics, and the patient’s overall quality of life. Guided and Bone Tissue Regeneration (GTR/BTR) are surgical therapies based on the placement of a membrane that prevents epithelial growth into the defect, allowing the periodontal/bone cells (including stem cells) to regenerate or restore the affected tissues. The success of these therapies is commonly affected by the local bacterial colonization of the membrane area and its fast biodegradation, causing postoperative infections and a premature rupture of the membrane limiting the regeneration process. This study presents the antibacterial and osteogenic differentiation properties of polycaprolactone-gelatin (PCL-G) electrospun membranes modified with ZnO nanoparticles (ZnO-NPs). The membranes´ chemical composition, surface roughness, biodegradation, water wettability, and mechanical properties under simulated physiological conditions, were analyzed by the close relationship with their biological properties. The PCL-G membranes modified with 1, 3, and 6% w/w of ZnO-NPs showed a significant reduction in the planktonic and biofilm formation of four clinically relevant bacteria; A. actinomycetemcomitans serotype b, P. gingivalis, E. coli, and S. epidermidis. Additionally, the membranes presented appropriate mechanical properties and biodegradation rates to be potentially used in clinical treatments. Notably, the membranes modified with the lowest concentration of ZnO-NPs (1% w/w) stimulated the production of osteoblast markers and calcium deposits in human bone marrow-derived mesenchymal stem cells (BM-MSC) and were biocompatible to human osteoblasts cells (hFOB). These results suggest that the PCL-G membranes with 1% w/w of ZnO-NPs are high-potential candidates for GTR/BTR treatments, as they were the most effective in terms of better antibacterial effectiveness at a lower NPs-concentration while creating a favorable cellular microenvironment for bone growth.

A tailored bioactive 3D porous poly(lactic-acid)-exosome scaffold with osteo-immunomodulatory and osteogenic differentiation properties

Polylactic acid (PLA) is a versatile and biodegradable scaffold widely used in biomedical fields to repair tissue defects. Exosomes derived from mesenchymal stem cells (MSCs) are nano-sized extracellular vesicles, which play an important role in tissue engineering in recent years. The primary focus of this study was to develop a bioactive 3D PLA scaffold using exosome-based strategy to improve its osteogenic and immunoregulatory potential. We firstly successfully isolated MSC-derived exosomes (MSC-Exo). Morphological analysis revealed that MSC-Exo exhibits a typical cup-shaped morphology with high expression of exosomal marker CD63. MSC-Exo internalization into recipient cells were also investigated using flow cytometry and confocal laser scanning microscopy. Porous 3D PLA scaffold coated MSC-Exo were used for immunoregulatory and osteogenic testing. Exosomes released from 3D PLA scaffold were validated in RAW264.7 and hBMSCs. The cell proliferation and live/dead assay indicated high biocompatibility for PLA-Exo scaffold. Additionally, PLA-Exo scaffold could reduce the pro-inflammatory marker expression and reactive oxygen species (ROS) production, indicating potential immunoregulatory potential. It is also confirmed that PLA-Exo scaffold could potentiate osteogenic differentiation in the osteogenesis assay. In conclusion, our results demonstrate this bioactive 3D-printed PLA scaffolds with MSC-Exo modification holds immunoregulatory potential and favor osteogenic differentiation, thus having potential applications in bone tissue regeneration.

An efficient approach to endow TiNbTaZr implant with osteogenic differentiation and antibacterial activity in vitro

Osteogenic differentiation and antibacterial property are two-core requirements for bone implants, but typically they are not compatible. Zinc (Zn) as a common bioactive material is widely used in the medical field. A balance between antibacterial and osteogenic activity can be achieved at appropriate Zn concentration. In this study, the TNTZ/Zn micro/nano-composites were prepared by doping Zn nanoparticles onto Ti-35Nb-2Ta-3Zr (TNTZ) surface through the friction stir processing (FSP) technique. The results of material characterization revealed the homogeneous distribution of Zn, the presence of α″ martensite, and the increase in microhardness in the stir zone. Due to the solid metallurgical bonding between Zn NPs and substrate, Zn ions were released slowly and may be biologically responsive through body fluid corrosion. In terms of biological activity, the expression of adhesion-related protein vinculin and osteogenic differentiation genes were up-regulated by TNTZ/Zn, which improved the early adhesion and osteogenic differentiation of bone marrow stromal stem cells. Besides, TNTZ/Zn presented excellent antibacterial properties, and direct contact with the fine grain surface containing Zn NPs may be the dominant mechanism. TNTZ/Zn micro/nano-composites have excellent mechanical properties, osteogenic differentiation and antibacterial properties, providing an efficient strategy for titanium alloy surface modification and showing tremendous potential in dental applications.

Characterization of Dental Pulp Stem Cells Response to Bone Substitutes Biomaterials in Dentistry

Bone substitute biomaterials (BSBs) represent a promising alternative to bone autografts, due to their biocompatibility, osteoconduction, slow resorption rates, and the ability to define and maintain volume for bone gain in dentistry. Many biomaterials are tailored to provide structural and biological support for bone regeneration, and allow the migration of bone-forming cells into the bone defect. Neural crest-derived stem cells isolated from human dental pulp (hDPSCs) represent a suitable stem cell source to study the biological effects of BSBs on osteoprogenitor cells involved in the physiological bone regenerative processes. This study aimed to evaluate how three different BSBs affect the stem cell properties, osteogenic differentiation, and inflammatory properties of hDPSCs. Our data highlight that BSBs do not alter cell proliferation and stemness markers expression, nor induce any inflammatory responses. Bone metabolism data show that hDPSCs exposed to the three BSBs distinctively secrete the factors supporting osteoblast activity and osteoclast activity. Our data indicate that (i) hDPSCs are a suitable stem cell source to study the effects of BSBs, and that (ii) the formulation of BSBs may condition the biological properties of stem cells, suggesting their versatile suitability to different dentistry applications.

Notoginsenoside R1 Promotes Migration, Adhesin, Spreading, and Osteogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stromal Cells.

Cellular activities, such as attachment, spreading, proliferation, migration, and differentiation are indispensable for the success of bone tissue engineering. Mesenchymal stromal cells (MSCs) are the key precursor cells to regenerate bone. Bioactive compounds from natural products had shown bone regenerative potential. Notoginsenoside R1 (NGR1) is a primary bioactive natural compound that regulates various biological activities, including cardiovascular protection, neuro-protection, and anti-cancer effects. However, the effect of NGR1 on migration, adhesion, spreading, and osteogenic differentiation of MSCs required for bone tissue engineering application has not been tested properly. In this study, we aimed to analyze the effect of NGR1 on the cellular activities of MSCs. Since human adipose-derived stromal cells (hASCs) are commonly used MSCs for bone tissue engineering, we used hASCs as a model of MSCs. The optimal concentration of 0.05 μg/mL NGR1 was biocompatible and promoted migration and osteogenic differentiation of hASCs. Pro-angiogenic factor VEGF expression was upregulated in NGR1-treated hASCs. NGR1 enhanced the adhesion and spreading of hASCs on the bio-inert glass surface. NGR1 robustly promoted hASCs adhesion and survival in 3D-printed TCP scaffold both in vitro and in vivo. NGR1 mitigated LPS-induced expression of inflammatory markers IL-1β, IL-6, and TNF-α in hASCs as well as inhibited the RANKL/OPG expression ratio. In conclusion, the biocompatible NGR1 promoted the migration, adhesion, spreading, osteogenic differentiation, and anti-inflammatory properties of hASCs.

(Zn, Ni)-ferrite nanoparticles for promoted osteogenic differentiation of MC3T3-E1 cells

The structural composition and functionality of bone tissues has been significantly impacted due to progressive ageing, thereby necessitating effective strategies that are not just about temporary cure but about permanent regeneration of tissues, one such being regenerative medicine. Of the several novelties in the field, the provocation of osteogenesis involving nanoparticles has gained significant attention for their heightened efficiency and cost effectiveness. Magnetic materials in particular have been increasingly paid attention to owing to their edge over stability, non-toxicity and feasibility to spatially track using MRI. The present study involves the synthesis of Zn and Ni doped ferrite ((Zn, Ni)-ferrite) nanoparticles involving chemical co-precipitation method. The materials were evaluated against MC3T3 cells towards ROS induced osteogenic differentiation properties, and the results implied very less toxicity even at concentration surpassing 50 µg/ml in addition to the void of necrosis after treatment with 2.5 and 5 µg/ml of (Zn, Ni)-ferrite. FACS results implied 1% cell staining with propidium iodide after 24 h exposure at 2.5 µg/ml concentrations of (Zn, Ni)-ferrite, thereby substantiating (Zn, Ni)-ferrite as a potential biomaterial in favor of regenerative medicine.

3D bioprinted GelMA/GO composite induces osteoblastic differentiation.

Graft substitute is a mature treatment tool in craniofacial bone repair. However, stress shielding and immutability of structure limit its use in patients with congenital defects. Therefore, a regenerative graft would be best suited for repair. Mesenchymal stem cells (MSCs) have been shown to be feasible in regenerative medicine and the clinical treatment of bone repair. The aim of this study was to propose a strategy that would directly blend graphene oxide (GO) and MSCs with gelatin methacrylate anhydride (GelMA), as bioink, to generate the scaffold for bone regenerative repair. The survival and osteogenic capacity of MSCs in the composite bioink were assessed by cell viability and proliferation assays, along with expression analysis of osteogenesis-related genes and proteins, and targeted immunofluorescence. The introduction of GO to the printing process had no influence on cell printing, viability, or printability of GelMa. However, the GO-involved structure exhibited a positive influence on MSC proliferation, without significantly affecting cell viability. Alkaline phosphatase was expressed more in cells cultured with GO than in those with pure GelMA. In addition, GO promoted the expression of osteogenesis-related genes and proteins, such as osteopontin, osteocalcin, and RUNX2. Collectively, the composite bioink enhanced cell proliferation and adhesion, as well as osteogenic differentiation properties, compared with pure GelMA.

Bioinformatics-Guided Analysis Uncovers AOX1 as an Osteogenic Differentiation-Relevant Gene of Human Mesenchymal Stem Cells.

Background: The available therapeutic options of bone defects, fracture nonunion, and osteoporosis remain limited, which are closely related to the osteogenic differentiation of bone marrow–derived mesenchymal stem cells (BMSCs). Thus, there remains an urgent demand to develop a prediction method to infer osteogenic differentiation–related genes in BMSCs. Method: We performed differential expression analysis between hBMSCs and osteogenically induced samples. Association analysis, co-expression analysis, and PPI analysis are then carried out to identify potential osteogenesis-related regulators. GO enrichment analysis and GSEA are performed to identify significantly enriched pathways associated with AOX1. qRT-PCR and Western blotting were employed to investigate the expression of genes on osteogenic differentiation, and plasmid transfection was used to overexpress the gene AOX1 in hBMSCs. Result: We identified 25 upregulated genes and 17 downregulated genes. Association analysis and PPI network analysis among these differentially expressed genes show that AOX1 is a potential regulator of osteogenic differentiation. GO enrichment analysis and GSEA show that AOX1 is significantly associated with osteoblast-related pathways. The experiments revealed that AOX1 level was higher and increased gradually in differentiated BMSCs compared with undifferentiated BMSCs, and AOX1 overexpression significantly increased the expression of osteo-specific genes, thereby clearly indicating that AOX1 plays an important role in osteogenic differentiation. Moreover, our method has ability in discriminating genes with osteogenic differentiation properties and can facilitate the process of discovery of new osteogenic differentiation–related genes. Conclusion: These findings collectively demonstrate that AOX1 is an osteogenic differentiation-relevant gene and provide a novel method established with a good performance for osteogenic differentiation-relevant genes prediction.

Endowing Polyetheretherketone Implants with Osseointegration Properties: In Situ Construction of Patterned Nanorod Arrays.

Polyetheretherketone (PEEK) is widely used in orthopedic and craniomaxillofacial surgeries as it exhibits excellent biocompatibility, mechanical property, and chemical stability. However, its clinical application is limited by the biological inertness of PEEK. Numerous efforts have been made to improve the bioactivity of this polymer over the years. However, modification methods that can not only promote osteogenesis but also maintain excellent properties are still limited. Hence, a facile hot die formation technique is developed for establishing patterned nanorod arrays on the PEEK surface in situ. This method can maintain the excellent properties of PEEK and can be used in implantation as it can facilitate osteogenic activity in the absence of any organic/inorganic differentiation-inducing factors. PEEK with 200-nm patterned nanorod arrays on the surface exhibits excellent osteogenic properties. This result is obtained by assessing the osteogenic differentiation properties of rat adipose-derived stem cells at the gene and protein levels in vitro. In vivo experimental results reveal that the surface-modified cylindrical PEEK 200 implants present with excellent osseointegration properties. Moreover, they can tightly bind with the surrounding bone tissue. A practical method for manufacturing single-component PEEK implants with excellent osseointegration properties is reported, and the materials can be possibly used as orthopedic implants.

Multifunctional polyethylene imine hybrids decorated by silica bioactive glass with enhanced mechanical properties, antibacterial, and osteogenesis for bone repair

Inorganic/organic hybrids and bioactive glasses demonstrate promising potential as bone substitute biomaterials. A sol-gel hybrid consisting of silica bioactive glass and biodegradable polymer can combine the high bioactivity of a glass with the toughness of a polymer. In this study, multifunctional hybrids with a combination of organic-inorganic hybrid structure class II consisting of polyethyleneimine (PEI) generation 4 (G4) and bioactive glass with enhanced mechanical properties, mineralization, antibacterial, and osteogenesis activities were synthesized by the sol-gel method. Glycidoxypropyl) trimethoxysilane (GPTMS) with different concentrations was used as a covalent bonding agent between PEI polymer and bioactive glass. The effect of GPTMS content was assessed in the presence and absence of calcium in the hybrid structures in terms of morphology, wettability, mechanical properties, antibacterial activity, cell viability, and in vitro osteogenic differentiation properties. By increasing the amount of GPTMS, the compressive strength increased from 1.95 MPa to 2.34 MPa, which was comparable to human trabecular bone. All the hybrids presented antibacterial activity against Staphylococcus aureus, forming an inhibition zone of 13–16 mm. An increase in cell viability of 82.22% in PSCaG90 was obtained after 1 day of MG-63 cell culture. Alkaline phosphatase expression and mineralization of MG-63 cells increased in the PSCaG90 hybrid in the absence of an osteogenic medium compared to PSG60 and PSG90. The PSCaG90 hybrid indicated considerable in vitro osteogenic capacity in the absence of a differentiation medium, expressing high levels of bone-specific proteins including collagen I (COL1A1), Runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osteocalcin (OCN), compared to calcium-free hybrids. Overall, our results suggest that the presence of calcium in the PSCaG90 leads to a significant increase in osteogenic differentiation of MG-63 cells even in the absence of differentiation medium, which suggests these hybrid structures with multifunctional properties as promising candidates for bone repair.