Graphene and its derivatives have good physical and chemical properties and biological properties, which can promote stem cell proliferation and osteogenic differentiation, and it has antibacterial properties and drug release property. Therefore, it has broad application prospects in the field of orthopedic biomaterials. This paper mainly introduces the research progress of graphene nanocomposite materials applied in the aspects of bone tissue engineering scaffold, bone repair, bone graft materials, etc. in order to provide desirable information for the future application basis and clinical research.
ObjectiveTo summarize the latest research progress of graphene and its derivatives (GDs) in bone repair. MethodsThe relevant research literature at home and abroad in recent years was extensively accessed. The properties of GDs in bone repair materials, including mechanical properties, electrical conductivity, and antibacterial properties, were systematically summarized, and the unique advantages of GDs in material preparation, functionalization, and application, as well as the contributions and challenges to bone tissue engineering, were discussed. ResultsThe application of GDs in bone repair materials has broad prospects, and the functionalization and modification technology effectively improve the osteogenic activity and material properties of GDs. GDs can induce osteogenic differentiation of stem cells through specific signaling pathways and promote osteogenic activity through immunomodulatory mechanisms. In addition, the parameters of GDs have significant effects on the cytotoxicity and degradation behavior.ConclusionGDs has great potential in the field of bone repair because of its excellent physical and chemical properties and biological properties. However, the cytotoxicity, biodegradability, and functionalization strategies of GDs still need to be further studied in order to achieve a wider application in the field of bone tissue engineering.
Objective To explore the construction and biocompatibility in vitro evaluation of the electrospun-graphene (Gr)/silk fibroin (SF) nanofilms. Methods The electrostatic spinning solution was prepared by dissolving SF and different mass ratio (0, 5%, 10%, 15%, and 20%) of Gr in formic acid solution. The hydrophilia and hydrophobic was analyzed by testing the static contact angle of electrostatic spinning solution of different mass ratio of Gr. Gr-SF nanofilms with different mass ratio (0, 5%, 10%, 15%, and 20%, as groups A, B, C, D, and E, respectively) were constructed by electrospinning technology. The structure of nanofilms were observed by optical microscope and scanning electron microscope; electrochemical performance of nanofilms were detected by cyclic voltammetry at electrochemical workstation; the porosity of nanofilms were measured by n-hexane substitution method, and the permeability were observed; L929 cells were used to evaluate the cytotoxicity of nanofilms in vitro at 1, 4, and 7 days after culture. The primary Sprague Dawley rats’ Schwann cells were co-cultured with different Gr-SF nanofilms of 5 groups for 3 days, the morphology and distribution of Schwann cells were identified by toluidine blue staining, the cell adhesion of Schwann cells were determined by cell counting kit 8 (CCK-8) method, the proliferation of Schwann cells were detected by EdU/Hoechst33342 staining. Results The static contact angle measurement confirmed that the hydrophilia of Gr-SF electrospinning solution was decreased by increasing the mass ratio of Gr. Light microscope and scanning electron microscopy showed that Gr-SF nanofilms had nanofiber structure, Gr particles could be dispersed uniformly in the membrane, and the increasing of mass ratio of Gr could lead to the aggregation of particles. The porosity measurement showed that the Gr-SF nanofilms had high porosity (>65%). With the increasing of mass ratio of Gr, the porosity and conductivity of Gr-SF nanofilm increased gradually, the value in the group A was significantly lower than those in groups C, D, and E (P<0.05). In vitro L929 cells cytotoxicity test showed that all the Gr-SF nanofilms had good biocompatibility. Toluidine blue staining, CCK-8 assay, and EdU/Hoechst33342 staining showed that Gr-SF nanofilms with mass ratio of Gr less than 10% could support the survival and proliferation of co-cultured Schwann cells. Conclusion The Gr-SF nanofilm with mass ratio of Gr less than 10% have proper hydrophilia, conductivity, porosity, and other physical and chemical properties, and have good biocompatibility in vitro. They can be used in tissue engineered nerve preparation.
Objective To review the research progress of graphene and its derivatives in repair of peripheral nerve defect. Methods The related literature of graphene and its derivatives in repair of peripheral nerve defect in recent years was extensively reviewed. Results It is confirmed by in vitro and in vivo experiments that graphene and its derivatives can promote cell adhesion, proliferation, differentiation and neurite growth effectively. They have good electrical conductivity, excellent mechanical properties, larger specific surface area, and other advantages when compared with traditional materials. The three-dimensional scaffold can improve the effect of nerve repair. Conclusion The metabolic pathways and long-term reaction of graphene and its derivatives in the body are unclear. How to regulate their biodegradation and explain the electric coupling reaction mechanism between cells and materials also need to be further explored.
We prepared silver nanoparticles/polyethyleneimine-reduction graphene oxide (AgNP/rGO-PEI) composite materials, and evaluated their quality performance in our center. Firstly, we prepared AgNP/rGO-PEI, and then analysed its stability, antibacterial activity, and cellular toxicity by comparing the AgNP/rGO-PEI with the silver nanoparticles (PVP/AgNP) modified by polyvinylpyrrolidone. We found in the study that silver nanoparticles (AgNP) distributed relatively uniformly in AgNP/rGO-PEI surface, silver nanoparticles mass fraction was 4.5%, and particle size was 6-13 nm. In dark or in low illumination light intensity of 3 000 lx meter environment (lux) for 10 days, PVP/AgNP aggregation was more obvious, but the AgNP/rGO-PEI had good dispersibility and its aggregation was not obvious; AgNP/rGO-PEI had a more excellent antibacterial activity, biological compatibility and relatively low biological toxicity. It was concluded that AgNP/rGO-PEI composite materials had reliable quality and good performance, and would have broad application prospects in the future.
Objective To investigate the role of composite graphene-protein hydrogels in repairing spinal cord injury (SCI) and promoting neural regeneration in rats. MethodsA composite graphene-protein hydrogel was prepared using the radical copolymerization method. Its physical properties, including adhesion, were evaluated through shear testing, and cytotoxicity was assessed using the MTT assay. Twenty-four adult female Sprague-Dawley rats were randomly divided into four groups: sham surgery, injury, hydrogel, and hydrogel+graphene groups (6 rats per group). The sham surgery group only exposed the T10 spinal cord tissue. The other three groups underwent laminectomy combined with spinal cord tissue block resection to establish a T10 SCI model. Post-modeling, the hydrogel group and the hydrogel+graphene group received implants of the protein hydrogel and composite graphene-protein hydrogels, respectively, at the injury defect site. The injury group received no additional implant treatment. Postoperative survival rates were monitored across groups. Hindlimb motor function recovery was assessed weekly via Basso-Beattie-Bresnahan (BBB) scores during the 12-week postoperative period. At 12 weeks, motor-evoked potentials were measured to assess neurophysiological function. T10 spinal cord tissue was harvested for histopathological examination via HE staining, followed by immunofluorescence staining for glial fibrillary acidic protein (GFAP), Laminin, and 5-hydroxytryptamine (5-HT) immunofluorescence staining to observe glial scar formation and axonal regeneration at the injury site. ResultsShear testing and MTT assays demonstrated that the composite graphene-protein hydrogels exhibited excellent underwater adhesion and biocompatibility. All rats in each group survived until the end of the experiment. During 12-week postoperative period, the BBB scores in the hydrogel and hydrogel+graphene groups showed a sustained upward trend over time (P<0.05). At 12 weeks after operation, BBB scores were significantly higher in the hydrogel and hydrogel+graphene groups than in the injury group, in the hydrogel+graphene group than in the hydrogel group, showing significant differences between groups (P<0.05). Neurophysiological testing revealed that the motor evoked potential amplitude in the hydrogel+graphene group was significantly higher than that in the injury group and the hydrogel group (P<0.05), with no significant difference compared to the sham surgery group (P>0.05). HE staining revealed that the hydrogel+graphene group exhibited spinal cord morphology most similar to the sham surgery group, with significantly restored tissue structural integrity and minimal vacuolation and inflammatory cell infiltration. Quantitative immunofluorescence analysis revealed that the relative fluorescence intensity of GFAP and Laminin in the injury group was significantly higher than that in the other groups (P<0.05). The relative fluorescence intensity of GFAP and Laminin in the hydrogel+graphene group was significantly lower than that in the hydrogel group (P<0.05). The relative fluorescence intensity of 5-HT in the injury group was significantly lower than that in the other groups (P<0.05). The relative fluorescence intensity of 5-HT in the hydrogel+graphene group was significantly higher than that in the hydrogel group (P<0.05), with no significant difference compared to the sham surgery group (P>0.05). ConclusionThe composite graphene-protein hydrogels effectively repairs SCI in rats by significantly inhibiting glial scar formation at the injury site, promoting 5-HT-positive axonal regeneration, and improving post-injury neurophysiological function and hindlimb motor recovery. It represents a spinal cord repair material with potential clinical application value.