Large bone defect repair is a difficult problem to be solved urgently in orthopaedic field, and the application of bone repair materials is a feasible method to solve this problem. Therefore, bone repair materials have been continuously developed, and have evolved from autogenous bone grafts, allograft bone grafts, and inert materials to highly active and multifunctional bone tissue engineering scaffold materials. In this paper, the related mechanism of bone repair materials, the application of bone repair materials, and the exploration of new bone repair materials are introduced to present the research status and advance of the bone repair materials, and the development direction is also prospected.
With the in-depth research on bone repair process, and the progress in bone repair materials preparation and characterization, a variety of artificial bone substitutes have been fully developed in the treatment of bone related diseases such as bone defects. However, the current various natural or synthetic biomaterials are still unable to achieve the structure and properties of natural bone. Carbon nanotubes (CNTs) have provided a new direction for the development of new materials in the field of bone repair due to their excellent structural stability, mechanical properties, and functional group modifiability. Moreover, CNTs and their composites have broad prospects in the design of bone repair materials and as drug delivery carriers. This paper describes the advantages of CNTs related to bone tissue regeneration from the aspects of morphology, chemistry, mechanics, electromagnetism, and biosafety, as well as the application of CNTs in drug delivery carriers and reinforcement components of scaffold materials. In addition, the potential problems and prospects of CNTs in bone regenerative medicine are discussed.
Objective To evaluate the effect of methylation determination about the peripheral plasma DNA in diagnose of hepatocellular carcinoma (HCC) and select the highly sensitive and specific methylated cancer suppressor genes. Methods Methylation-specific PCR (MSP) was used to detect the degree of methylation about SLIT2 and DAPK genes in peripheral plasma and associated cancer tissues of 34 patients with HCC confirmed by pathology, then analyzed their relationship to clinicopathologic feature. Results The positive rate of the promoter methylation of SLIT2 and DAPK genes in cancer tissues in 34 cases were 70.6% (24/34) and 79.4% (27/34), while the relevant promoter methylation rate in plasma were 44.1% (15/34) and 50.0% (17/34) correspondingly. The sensitivity of detection of DNA methylation about SLIT2 and DAPK genes in plasma was 62.5% and 63.0%, respectively;both of the specificity for them were 100%. The negative predicted value was 52.6% and 41.2%, respectively;while both of the positive predicted value were 100%. There were no significant correlation between the clinicopathologic features and the methylation rate in cancer tissues and plasma (P>0.05). In plasma of patients whose AFP<400 μg/L, the positive rate of combined detection of DNA methylation of SLIT2 and DAPK was 61.1% (11/18). Conclusions The detection rate of DNA methylation of SLIT2 and DAPK genes in plasma is higher, and there is a significant correlation between the DNA methylation in HCC tissue and plasma, based on MSP method. DNA methylation in plasma, as an non-invasive method, could be used to diagnose HCC, especially for the patients whose AFP is negative. HBV infection may be only associate with DNA methylation of part gene.
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.
ObjectiveTo review the application of cell derived decellularized extracellular matrix (CDM) in tissue engineering. Methods The literature related to the application of CDM in tissue engineering was extensively reviewed and analyzed. Results CDM is a mixture of cells and their secretory products obtained by culturing cells in vitro for a period of time, and then the mixture is treated by decellularization. Compared with tissue derived decellularized extracellular matrix (TDM), CDM can screen and utilize pathogen-free autologous cells, effectively avoiding the possible shortcomings of TDM, such as immune response and limited sources. In addition, by selecting the cell source, controlling the culture conditions, and selecting the template scaffold, the composition, structure, and mechanical properties of the scaffold can be controlled to obtain the desired scaffold. CDM retains the components and microstructure of extracellular matrix and has excellent biological functions, so it has become the focus of tissue engineering scaffolds. ConclusionCDM is superior in the field of tissue engineering because of its outstanding adjustability, safety, and high bioactivity. With the continuous progress of technology, CDM stents suitable for clinical use are expected to continue to emerge.