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BACKGROUND:At present,nanocomposite gelatin methacryloyl hydrogels have been extensively studied in bone tissue engineering. OBJECTIVE:To review the latest research progress of nanocomposite gelatin methacryloyl hydrogels,and introduce the application of nanocomposite gelatin methacryloyl hydrogels in different bone defect environments. METHODS:The computer retrieval was conducted for relevant literature published in CNKI,WanFang,PubMed,and Web of Science databases from 2016 to 2023.The Chinese and English search terms were"gelatin,methacryl*,nano*,bone,bone tissue engineering,bone regeneration,osteogenesis". RESULTS AND CONCLUSION:(1)Up to now,inorganic nanomaterials,organic nanomaterials and organic-inorganic hybrid nanomaterials are the main nanomaterials used as fillers for gelatin methacryloyl.(2)Inorganic nanomaterials enhance the mechanical strength of gelatin methacryloyl,improve its thixotropic properties and degradation rate,and realize the antibacterial,osteogenic,immunoregulatory,angiogenic and other functions of gelatin methacryloyl hydrogel through its surface charge regulation,drug/factor loading,metal ion self-degradation release,etc.(3)Organic nanomaterial and organic-inorganic hybrid nanomaterial composite gelatin methacryloyl hydrogel are two emerging materials.At present,there are relatively few studies,but from the published research,compared with inorganic nanomaterial gelatin methacryloyl hydrogel,organic nanomaterial gelatin methacryloyl hydrogel has better biocompatibility and drug-loading performance.The interaction between nano phase and organic polymer phase is stronger,and the dispersion of nano particles is better.(4)Organic-inorganic hybrid nanomaterial composite gelatin methacryloyl combines the advantages of the previous two,and has better controllability of metal ion release,which proves great research potential.(5)Nanomaterials can enhance the antibacterial,immune regulation,osteogenesis and other biological properties of gelatin methacryloyl,so as to promote bone regeneration in the complex bone defect microenvironment,such as infected bone defect,diabetes,osteosarcoma resection and so on.However,the relevant research of nanocomposite gelatin methacryloyl hydrogel in bone repair is still limited to animal experiments.Further safety testing and clinical studies are still needed.
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BACKGROUND:Scaffold materials serve as platforms that provide space and structure,playing a crucial role in the regeneration of cartilage tissue.Scholars from around the world are exploring different approaches to fabricate more ideal scaffold materials. OBJECTIVE:To review the design principles and preparation methods of cartilage scaffolds,and to further explore the advantages and limitations of various preparation methods. METHODS:Literature searches were conducted on the databases of CNKI,WanFang Data,PubMed,and FMRS from 1998 to 2023.The search terms were"cartilage repair,cartilage tissue engineering,cartilage scaffold materials,preparation"in Chinese and English.A total of 57 articles were ultimately reviewed. RESULTS AND CONCLUSION:(1)The articular cartilage has a unique structure and limited self-repair capacity after injury.Even if self-repair occurs,the newly formed cartilage is typically fibrocartilage,which is far inferior to normal articular cartilage in terms of structure and mechanical properties.It is difficult to maintain normal function and often leads to degenerative changes.Currently,the design and fabrication of scaffold materials for cartilage repair need to consider the following aspects:biocompatibility and biodegradability,suitable pore structure and porosity,appropriate mechanical properties,and bioactivity.(2)Research on the preparation of cartilage scaffolds has made significant progress,continuously introducing new preparation methods and optimization strategies.These methods have their advantages and disadvantages,providing more possibilities for customized preparation and functional design of cartilage scaffolds according to specific requirements.
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BACKGROUND:Bone is a remarkable natural material possessing piezoelectric properties.By harnessing the biomimetic piezoelectric effect,tissue engineering materials can be employed to effectively address bone tissue defects and facilitate their repair. OBJECTIVE:Using a solid-phase force chemistry technique,a piezoelectric scaffold with inherent osteogenic properties was meticulously fabricated.This unique scaffold was then assessed for its impact on osteoblast adhesion,proliferation,and osteogenic differentiation. METHODS:Polyvinylidene fluoride(PVDF)powders,along with commercially available NaCl(mass ratios are 60:40,50:50,40:60,and 30:70,respectively),were subjected to solid-phase shear milling technology,resulting in a homogenous mixture.Through a melting process,a substantial material was formed,and subsequent treatment with a pure water solution effectively eliminated the NaCl.Consequently,PVDF piezoelectric foam scaffolds with varying pore sizes were successfully prepared.These materials were categorized as PVDF-40,PVDF-50,PVDF-60,and PVDF-70,denoting the respective mass percentages of NaCl during preparation.The surface morphology,crystal phase composition,thermodynamic behavior,mechanical properties,and piezoelectric properties of each group were meticulously characterized.The four kinds of piezoelectric foam scaffolds were co-cultured with the MG63 osteoblast cell line to evaluate its biocompatibility and potential to promote bone differentiation. RESULTS AND CONCLUSION:(1)The scanning electron microscopy,four groups of scaffolds had multi-level pores.As the NaCl mass fraction in the mixed powder increased,the porosity of the scaffolds increased.X-ray energy dispersion spectrum,X-ray diffraction,Fourier transform infrared spectroscopy,and thermogravimetric analysis collectively revealed the scaffold predominantly comprised the α phase,which inherently lacked piezoelectric properties.However,the application of solid-phase force chemistry successfully stimulated the formation of the β phase,thereby enhancing the scaffold's piezoelectric properties.Notably,the PVDF-60 group exhibited the highest proportion of the β phase among all the tested groups.The results of cyclic compression testing and piezoelectric performance assessment demonstrated that the PVDF-60 group exhibited superior compressive strength and piezoelectric performance compared to the other groups.(2)The findings from scanning electron microscopy and laser confocal microscopy exhibited that MG63 cells adhered well to the surface of the four groups of scaffolds,with good morphology,extended more pseudopods,and secreted a large amount of extracellular matrix.CCK-8 assay revealed that the proliferative absorbance of PVDF-60 cells cultured for 4 days was higher than that of the other three groups(P<0.000 1).Alkaline phosphatase staining and alizarin red staining showed that the expression of alkaline phosphatase and the number of calcified nodules in the PVDF-60 group were higher than those in the other three groups(P<0.01,P<0.000 1).(3)The piezoelectric PVDF foam-based scaffolds demonstrated favorable cytocompatibility.Notably,the PVDF-60 group showed superior mechanical properties,piezoelectric performance,and bone-inducing capabilities.
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BACKGROUND:Graphene is the thinnest,strongest,and toughest type of two-dimensional new crystal material,demonstrating significant advantages in biomedical applications.Angiogenesis and vascularization of bone are key factors in tissue repair and regeneration,and are effective ways to address vascular and osteogenic issues. OBJECTIVE:To review the characteristics and mechanisms of graphene and its derivatives in promoting angiogenesis activity and vascularizing bone,in order to provide a reference for their clinical application in vascular tissue repair and regeneration. METHODS:Using a computer to search for relevant literature included in PubMed,ScienceDirect,CNKI,and Wanfang databases,the Chinese search terms were"grapheme","angiogenesis,vascularization","vascularized bone",and"endothelial cells",while the English search terms were"graphene""angiogenesis OR vascularization""vascularized bone""endothelial cells".After excluding literature unrelated to the topic of the article,according to the inclusion and exclusion criteria,62 articles were ultimately included for result analysis. RESULTS AND CONCLUSION:(1)At present,graphene oxide has been studied more and is the most widely used in graphene and its derivatives.(2)Graphene and its derivatives are suitable for heart,bone,nerve,and wound healing related diseases.(3)Graphene and its derivatives have excellent physical and chemical properties and biological properties,but they have potential cytotoxicity.We should pay attention to its biological safety in application.(4)The application of graphene and its derivatives requires further research to demonstrate the optimal size and concentration and measures to reduce toxicity.(5)On the cellular level,graphene and its derivatives can promote angiogenic activity by tip endothelial cell phenotype,mesenchymal stem cell adhesion and proliferation, and vascular smooth muscle cell growth.(6)On the molecular level,graphene and its derivatives can increase the expression of vascular endothelial growth factor,basic fibroblast growth factor,hepatocyte growth factor and activate reactive oxygen species/nitric oxide synthase/nitric oxide signaling pathway,lysophosphatilate R6/Hippo-YAP pathway,stromal cell-derived factor-1/vascular endothelial growth factor and ZEB 1/Notch1 pathway.(7)Grapheme oxide and graphene oxide-copper phosphorylated extracellular regulatory protein kinase and activated hypoxia-inducible factor-1,thereby promoting the up-regulation of vascular endothelial growth factor and bone morphogenetic protein-2 expression,and promoting angiogenesis and vascularized bone.(8)In summary,graphene and its derivatives,especially graphene oxide,have great application prospects in the repair and regeneration of vascularized tissues due to their excellent biological properties,good angiogenesis and vascularized bone ability.
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BACKGROUND:With the proven ability of traditional Chinese medicine such as icariin and berberine to promote bone regeneration by regulating various mechanisms and targets,researchers have combined active ingredients of traditional Chinese medicine with bone tissue engineering and found that they have unique advantages in treating bone defects. OBJECTIVE:Starting from the active ingredients of traditional Chinese medicines that promote bone formation,to screen cases of their effective combination with different drug-carrying scaffold materials,and summarize the active ingredients of traditional Chinese medicines that have the potential to be applied to bone tissue engineering. METHODS:CNKI,WanFang,PubMed,and Web of Science were searched for relevant literature published from 2000 to 2023,using the keywords of"bone tissue engineering,bone tissue-engineered scaffold materials,bone defect,bone repair,bone regeneration,traditional Chinese medicine"in Chinese and English.According to the inclusion and exclusion criteria,87 papers were finally included for review. RESULTS AND CONCLUSION:There are various kinds of active ingredients of traditional Chinese medicine to promote bone regeneration,mainly including flavonoids,non-flavonoid polyphenols,alkaloids,glycosides.These active ingredients have anti-inflammatory and analgesic effects,promote osteoblasts,inhibit osteoclasts and promote early angiogenesis.The combination of active ingredients of traditional Chinese medicine with bone tissue engineering is effective in anti-inflammation,accelerating collagen and bone formation,and promoting the expression of osteogenic genes,which provides a theoretical basis for the application of traditional Chinese medicine in bone tissue regeneration,and at the same time provides a new idea for the repair of bone defects.
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BACKGROUND:Three-dimensional(3D)printing is an emerging technology in the field of dentistry.It utilizes a layer-by-layer manufacturing technique to create scaffolds suitable for periodontal tissue engineering applications.Tissue scaffolds produced through 3D printing can possess controlled characteristics,including internal structure,porosity,and interconnectivity,making it an ideal strategy for periodontal tissue engineering. OBJECTIVE:To review the applications of 3D printed scaffolds in periodontal regeneration. METHODS:English search terms were"3D printing,periodontal tissue engineering,additive manufacturing,regenerative medicine,bioengineering,scaffold,bioprinting,periodontitis".Chinese search terms were"3D printing,additive manufacturing,periodontal tissue engineering,scaffolds,bio-inks,bioprinting,tissue engineering".Relevant literature published from 2000 to 2023 in PubMed and CNKI databases was retrieved and included in the review. RESULTS AND CONCLUSION:Over the past few decades,3D printing technology has made significant progress and breakthroughs in tissue engineering and biomedical fields.3D printing technology can provide highly personalized treatment programs,improve the suitability and therapeutic effect of therapeutic stents,and has broad application prospects in periodontal tissue engineering.In periodontal tissue engineering,3D printing applications can better mimic the complex structures of biological tissues and manufacture biocompatible scaffold materials with suitable mechanical and rheological properties.The layer-by-layer construction of tissue engineering scaffolds through 3D printing not only enables the creation of precise and intricate scaffold models for personalized treatment of periodontal disease but also facilitates the incorporation of complex microstructures and channels within the scaffolds to promote cell growth and tissue regeneration.
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BACKGROUND:Berberine has the potential to induce osteogenic differentiation of various mesenchymal stem cells under normal conditions and special conditions such as high glucose,infection and inflammation.It is a natural small molecule drug that can induce bone formation in seed cells instead of growth factors,and has great application prospect in bone tissue engineering. OBJECTIVE:To review and summarize the research progress in the osteogenic mechanism and efficacy of berberine,especially its osteogenic potential under high glucose,infection and inflammation conditions,and its biological safety,so as to provide theoretical basis for its development and application in bone tissue engineering. METHODS:PubMed,WanFang,and CNKI were searched for relevant literature using the keywords of"berberine,bone defects,bone repair,bone regeneration,osteoinductive,osteoporosis,osteoblast,osteoclast,bone tissue engineering,bone,high glucose,diabetes,inflam*,infect*"in English and Chinese,respectively.A total of 105 literatures were selected for review. RESULTS AND CONCLUSION:Berberine can be used to treat multiple diseases including bone diseases,and it has the ability to promote bone regeneration.This article systematically reviews the mechanism of berberine on bone regeneration and in vivo and in vitro studies.Studies have shown that it can play a role in bone repair by promoting osteogenesis,inhibiting osteoclast formation and activity,and preventing osteoporosis.It shows excellent osteogenic differentiation potential mainly via Wnt/β-catenin,PI3K/AKT,EGFR/MEK/p38MAPK,cAMP/PKA/CREB,ERK and other signaling pathways.Berberine can also relieve the inhibition of osteogenic differentiation caused by high glucose,infection and inflammation,which provides more possibilities for the treatment of bone defects in patients with diabetes or infection and inflammation in the bone defect site.Berberine also has the advantages of low toxicity,low price,easy access(currently it can be synthesized),which is a relatively ideal bone induction potential drug.In recent years,the application of berberine in the treatment of bone defect tends to be localized,mainly through the combination with bone tissue engineering technology to improve bioavailability,and has shown good bone repair effect and excellent biological safety in animal experiments.In addition,preclinical experiments have shown splendid bone regeneration potential in the conditions of diabetes,local infection and inflammation.In the future,more studies are needed to fully reveal the osteogenic mechanism and biological safety of berberine,and seek the most suitable controlled release loading system to make artificial bone replacement materials with good mechanical strength,efficacy and biological safety.
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@#Graphene family nanomaterials (GFNs) are highly popular in the field of bone tissue engineering because of their excellent mechanical properties, biocompatibility, and ability to promote the osteogenic differentiation of stem cells. GFNs play a multifaceted role in promoting the bone regeneration microenvironment. First, GFNs activate the adhesion kinase/extracellularly regulated protein kinase (FAK/ERK) signaling pathway through their own micromorphology and promote the expression of osteogenesis-related genes. Second, GFNs adapt to the mechanical strength of bone tissue, which helps to maintain osseointegration; by adjusting the stiffness of the extracellular matrix, they transmit the mechanical signals of the matrix to the intracellular space with the help of focal adhesions (FAs), thus creating a favorable physiochemical microenvironment. Moreover, they regulate the immune microenvironment at the site of bone defects, thus directing the polarization of macrophages to the M2 type and influencing the secretion of relevant cytokines. GFNs also act as slow-release carriers of bioactive molecules with both angiogenic and antibacterial abilities, thus accelerating the repair process of bone defects. Multiple types of GFNs regulate the bone regeneration microenvironment, including scaffold materials, hydrogels, biofilms, and implantable coatings. Although GFNs have attracted much attention in the field of bone tissue engineering, their application in bone tissue regeneration is still in the basic experimental stage. To promote the clinical application of GFNs, there is a need to provide more sufficient evidence of their biocompatibility, elucidate the mechanism by which they induce the osteogenic differentiation of stem cells, and develop more effective form of applications.
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OBJECTIVE@#To construct polyhydroxyalkanoate (PHA) microspheres loaded with bone morphogenetic protein 2 (BMP-2) and human β-defensin 3 (HBD3), and evaluate the antibacterial activity of microspheres and the effect of promoting osteogenic differentiation, aiming to provide a new option of material for bone tissue engineering.@*METHODS@#The soybean lecithin (SL)-BMP-2 and SL-HBD3 were prepared by SL-mediated introduction of growth factors into polyesters technology, and the functional microsphere (f-PMS) containing BMP-2 and HBD3 were prepared by microfluidic technology, while pure microsphere (p-PMS) was prepared by the same method as the control. The morphology of microspheres was observed by scanning electron microscopy and the water absorption was detected; the release curves of BMP-2 and HBD3 in f-PMS were detected by ELISA kit. The antibacterial effect of microspheres in Staphylococcus aureus and Escherichia coli was tested with the LIVE/DEADTM BacLightTM bacterial staining kit; the biocompatibility of microspheres was tested using Transwell and cell counting kit 8 (CCK-8). The effect of microspheres on osteogenic differentiation was determined by collagen type Ⅰ (COL-1) immunofluorescence staining and alkaline phosphatase (ALP) concentration.@*RESULTS@#In this experiment, the f-PMS and p-PMS were successfully constructed. Morphological characteristics showed that p-PMS surface was rough and distributed with micropores of 1-3 μm, while f-PMS surface was smooth and existed white granular material. There was no significant difference in water absorption between the two groups (P>0.05). The release curves of BMP-2 and HBD3 in the f-PMS and p-PMS were basically the same, showing both early sudden release and late slow release. The antibacterial activity of f-PMS was significantly higher than that of p-PMS in the test that against Staphylococcus aureus and Escherichia coli (P<0.05), but there was no significant difference in biocompatibility between the two groups (P>0.05). The results of osteogenic differentiation of human BMSCs showed that the fluorescence intensity of osteogenic specific protein COL-1 of f-PMS was significantly higher than that in p-PMS, and the activity of ALP in f-PMS was also significantly higher than that in p-PMS (P<0.05).@*CONCLUSION@#The p-PHA have good antibacterial activity and biocompatibility, and can effectively promote the osteogenic differentiation of human BMSCs, which is expected to be applied to bone tissue engineering in the future.
Sujet(s)
Humains , Ostéogenèse , Polyhydroxyalcanoates , Microsphères , Phosphatase alcaline , Antibactériens/pharmacologie , Agents colorants , Escherichia coliRÉSUMÉ
@#Currently, cell transplantation in combination with scaffold materials are one of the main strategies in periodontal bone tissue engineering. In periodontal bone tissues, the stiffness and spatial structure of tissues such as alveolar bone and cementum differ, and the difference in mechanical properties of scaffolds also has disparate effects on the proliferation and differentiation of stem cells. Accumulating evidence shows that mechanical stimulating factors such as matrix stiffness and scaffold topography modulate biological behaviors of various seeding cells, including adipose-derived stem cells and periodontal ligament stem cells. A hard matrix can promote cytoskeletal stretching of stem cells, leading to nuclear translocation of Yes-associated protein (YAP) and promoting osteogenic differentiation by upregulating alkaline phosphatase (ALP) and osteocalcin (OCN) via the Wnt/β-catenin pathway. The topologic structure of scaffolds can affect cell adhesion and cytoskeletal remodeling, increase the hardness of cells and promote the osteogenic differentiation of stem cells. In this paper, the effects of mechanical stimulation on the differentiation of stem cells in periodontal bone tissue engineering are reviewed.
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BACKGROUND: It has been confirmed that some biomedical magnesium alloy products have antibacterial properties, but the specific antibacterial mechanism is still unclear. OBJECTIVE: To investigate the antibacterial properties of biomedical Jiao Da Bio-Magnesium scaffold in vitro and explore possible mechanism. METHODS: Jiao Da Bio-Magnesium porous scaffold material extract was prepared. As the most common bacteria causing orthopedic implants infection, Escherichia coli and Staphylococcus aureus were selected for testing. The bacteriostasis rate was quantitatively evaluated by contact culture of the extraction solution. The bacteriostasis performance of the material was qualitatively evaluated by observing the bacterial morphology through scanning electron microscope. The alkaline phosphatase, conductivity, potassium ion, nucleic acid and protein content in bacterial extracellular liquid environment were detected. The possible antibacterial mechanism of Jiao Da Bio-Magnesium porous scaffold material extract was preliminarily explored. RESULTS AND CONCLUSION: (1) The bacteriostasis rate of Jiao Da Bio-Magnesium porous scaffold extract cultured with Escherichia coli for 12 hours ranged from 56.23% to 79.72%, while the Staphylococcus aureus group ranged from 62.34% to 76.07%. (2) Under scanning electron microscope, wizened form, smaller volume and scarcer distribution were observed. (3) The material extract had no effect on the content of alkaline phosphatase in the extracellular environment of the two bacteria, but increased the electrical conductivity and potassium ion content in the extracellular environment of the two bacteria. (4) The material extract had no effect on the content of nucleic acid and protein in the extracellular environment of Escherichia coli, and increased the content of nucleic acid and protein in the extracellular environment of Staphylococcus aureus. (5) The material extract could inhibit the nucleic acid content of the two bacteria, but had no effect on the soluble protein content of Escherichia coli cells, and inhibited the synthesis of soluble protein in Staphylococcus aureus cells. (6) Results suggested that Jiao Da Bio-Magnesium porous scaffold material has certain antibacterial properties in vitro, and the inhibitory effect on Staphylococcus aureus is stronger than that on Escherichia coli. The possible antibacterial mechanism is speculated that it can change the permeability of bacterial cell membrane and affect the synthesis of bacterial nucleic acids and proteins.
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@#Defects in oral hard tissue caused by various factors have a negative impact on the functional and aesthetic results of prosthetic treatment. In recent years, the usage of bone tissue engineering for bone reconstruction has drawn widespread attention. Bone tissue engineering exhibits significant advantages, including the abundance of building materials and few side effects. In this paper, the composition and structure of dentin and its application in bone tissue engineering are reviewed, providing a new way to further optimize its performance. The results of a literature review show that the structure of dentin is very similar to that of autogenous bone. The inorganic component is mainly hydroxyapatite (HA), while the organic component is mainly collagen I, noncollagenous proteins (NCPs) and growth factors. Because of its unique composition, dentin can act as a scaffold and/or growth factor source through different processing methods. The deproteinization process removes most of the organic substances and creates a HA-based scaffold material with high porosity, which allows for vascularization and cellular infiltration. Demineralization increases dentin porosity by reducing the crystallinity of the mineralized components, so that part of HA, collagen fibers and growth factors are preserved. Demineralized dentin possesses various regulation functions ranging from differentiation, adhesion and proliferation of primitive cells and bone forming cell lineage. Extracted NCPs, as bioactive molecules, have been proved to play important roles that control cell differentiation, crystal nucleation and mineralization in bone formation. NCPs could be combined with variety of scaffold materials and modify their properties.
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@#Endothelial regeneration is a research hotspot in the field of dental pulp. The regeneration of endodontic blood flow is the bottleneck of dental pulp regeneration, and the applied scaffold material is the key to revascularization. Stent materials were reviewed. The literature review Results show that, depending on the source of the stent material used for endodontic revascularization, there are mainly natural, synthetic and composite materials. The natural scaffold materials used for vascular regeneration include chitosan, hyaluronic acid, bacterial cellulose, and proanthocyanidin; artificial scaffold materials include hydrogel, cryogel, and electrospinning. The bionic composite scaffold system with a double-layer tubular structure is low immunogenicity and good biocompatibility. Studies on the scaffold materials of bionic extracellular matrix, such as injectable hydrogels/microspheres, have promoted the development of dental pulp regeneration, that is, uniformly distributed scaffold materials in the root canal promote the generation of pulp-like tissue; Whether dental pulp tissue can establish effective blood circulation through the apical foramen remains a great challenge.
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BACKGROUND: Rapid development in tissue engineering research and technology makes dental pulp regeneration and revascularization possible. The interactions of stem cells, scaffolds and signaling factors in tissue engineering are particularly important. Whether stem cells can proliferate, differentiate and develop dental pulp-like tissue greatly depends on the choice of scaffolds OBJECTIVE: To review the widely studied and effective scaffold materials and two methods of scaffold preparation and analyze their applications in dental pulp reconstruction and their revascularization ability. METHODS: The first author searched PubMed, Wanfang and CNKI databases using a computer for relevant articles published between January 1, 2019 and September 30, 2019 with the search terms “pulp regeneration, pulp revascularization, scaffold” in English, and “pulp regeneration, pulp revascularization, revascularization, scaffold” in Chinese. A total of 421 English articles and 181 Chinese articles were retrieved. Finally, 61 articles were reviewed. RESULTS AND CONCLUSION: Platelet-derived scaffolds, extracellular-matrix-derived scaffolds, and self-assembling peptide take effect in pulp regeneration and revascularization. Composite materials combining natural and synthetic materials prepared by hydrogel and nanomaterial techniques exhibited advantages in cell proliferation, differentiation, migration, adherence, anti-inflammation, and factor delivery. The modified composite materials have a strong ability to promote vascularization. With the development of scaffold design and preparation technology based on hydrogels and nanomaterials, problems regarding insufficient scaffold source and unstable clinical effect will be solved in the future.
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BACKGROUND: Photocrosslinked alginate hydrogel has been a popular bone tissue engineering material because of its excellent biocompatibility and minimally invasive injection, but there are still problems such as insufficient strength and poor cell adhesion. OBJECTIVE: To construct the negatively charged hydrogels by introducing sodium methacrylate into photocrosslinked alginate hydrogels, and to explore the changes in its physical performance and cell adhesion. METHODS: After preparation of methacrylated alginate by reacting sodium alginate with 2-aminoethyl methacrylate, methacrylated alginate, photoinitiator and sodium methacrylate (0, 20, 40, 60 mmol/L) were homogeneously mixed. The negatively charged photocrosslinked alginate hydrogels were prepared under ultraviolet light. The functional groups of the hydrogels were analyzed by fourier transform infrared spectroscopy. The surface morphology of the hydrogels was observed by scanning electron microscopy and the swelling ratio was measured. MC3T3-E1 cells were cultured with each group of hydrogels for 48 hours, and the cytotoxicity of the hydrogels was investigated by cell counting kit-8 assay. MC3T3-E1 cells were seeded on the surface of each group of hydrogels. The early adhesion of the cells was observed by live/dead staining at the 4th hour, and cell spreading was observed on the 3rd day. RESULTS AND CONCLUSION: (1) Fourier transform infrared spectroscopy demonstrated that the introduction of sodium methacrylate could lead to a new peak at wavenumber of about 1 600 cm-1 in the hydrogel infrared wave, which was from the sodium methacrylate. (2) Scanning electron microscope observed that the density of the negatively charged photocrosslinked alginate hydrogels increased and the pore size of the gels decreased with augment of concentrations of sodium methacrylate. (3) The swelling ratio of the hydrogel decreased with the increase of the concentration of sodium methacrylate. (4) The live/dead staining revealed that the cells grew well on the surface of each hydrogel, and the cell viability reached above 95%. The cell counting kit-8 assay results showed that the negatively charged photocrosslinked alginate hydrogels had no cytotoxicity. (5) The early cell adhesion rate increased gradually and the cell extension became better with the increase of concentration of sodium methacrylate. (6) In summary, the introduction of sodium methacryl into photocrosslinked alginate hydrogels can adjust its physical properties and significantly improve its cell adhesion.
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BACKGROUND: The common clinical treatment methods of cardiovascular disease are vascular reconstruction, including stent interventional therapy, coronary artery bypass grafting and angioplasty. OBJECTIVE: To summarize the latest research progress of tissue-engineered vascular stent materials, such as natural derivative stent materials, synthetic macromolecule materials and composite materials, so as to lay a theoretical foundation for small-caliber vascular transplantation. METHODS: PubMed, WanFang, and CNI databases were retrieved for the articles published from January 2008 to July 2019. The key words were “tissue engineering, biological material, scaffold material, blood vessel” in Chinese and English, respectively. The documents with old content and repeated conclusions were excluded, and 52 eligible articles were enrolled. RESULTS AND CONCLUSION: Autologous vascular grafts, such as saphenous vein and internal thoracic artery, are the best alternatives to small-caliber vessels. However, restenosis of vascular lumen may be induced after transplantation, and the incidence of thrombosis, infection and transplantation failure increases, which seriously hinders the clinical application. Considering these limitations, researchers have embedded tissue-engineered vascular grafts into cells to produce a living material with physiological remodeling activity. This potential solution may bring hope for the future of vascular grafts.
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BACKGROUND: At present, there are many types of bone defect repair scaffolds, but a single type of material is difficult to meet the requirements of bone tissue engineering scaffold materials. Several suitable materials can be combined into a composite material by appropriate methods, taking into account the advantages and disadvantages of various materials. It is the focus of scholars in recent years. OBJECTIVE: To construct nano-hydroxyapatite/chitosan/polycaprolactone composite scaffolds and analyze characterization of composite scaffolds. METHODS: Nano-hydroxyapatite/chitosan/polycaprolactone porous ternary composite scaffold material was prepared by 3D printing and molding technology. The characterization of scaffold material was studied from X-ray diffraction analysis, stent water absorption rate, stent compressive strength, stent degradation performance in vitro, stent aperture analysis, scanning electron microscope analysis and other dimensions. RESULTS AND CONCLUSION: (1) X-ray diffraction analysis showed that the crystal-shaped peak map of nano-hydroxyapatite/chitosan/ polycaprolactone scaffold materials was similar to the hydroxyapatite powder diffraction standard card, suggesting that the scaffold materials were integrated with each other through physical interaction, and did not affect the biological function of hydroxyapatite. (2) The average water absorption rate of the scaffold was 18.28%, and the hydrophilicity was good. The maximum pressure that the scaffold could withstand was 1 415 N, and the degradation rate was similar to the osteogenic rate. (3) Under a microscope, a ternary scaffold material with an aperture of 250 µm was successfully produced. The pore size was uniform and distributed regularly. (4) Scanning electron microscope demonstrated that the fibers composed of chitosan and polycaprolactone were arranged orderly and grid like, hydroxyapatite was distributed uniformly on the fiber surface in granular form, and the ternary composite material presented uniform and loose microporous structure. (5) Nano-hydroxyapatite/chitosan/polycaprolactone ternary composite scaffold material can be successfully prepared through 3D printing and molding technology, which has moderate compressive strength, certain porosity, appropriate degradation rate and water absorption rate, and can lay a foundation for repairing bone defects.
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In sports system, the tendon-bone interface has the effect of tensile and bearing load, so the effect of healing plays a crucial role in restoring joint function. The process of repair is the formation of scar tissue, so it is difficult to achieve the ideal effect for morphology and biomechanical strength. The tissue engineering method can promote the tendon-bone interface healing from the seed cells, growth factors, and scaffolds, and is a new direction in the field of development of the tendon-bone interface healing.
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Objective: To summarize and analyze the research progress of scaffold materials used in tissue engineered meniscus. Methods: The classification and bionics design of scaffold materials were summarized by consulting domestic and foreign literature related to the research of tissue engineered meniscus in recent years. Results: Tissue engineered meniscus scaffolds can be roughly classified into synthetic polymers, hydrogels, extracellular matrix components, and tissue derived materials. These different materials have different characteristics, so the use of a single material has its unique disadvantages, and the use of a variety of materials composite scaffolds can learn from each other, which is a hot research area at present. In addition to material selection, material processing methods are also the focus of research. At the same time, according to the morphological structure and mechanical characteristics of the meniscus, the bionic design of tissue engineered meniscus scaffolds has great potential. Conclusion: At present, there are many kinds of scaffold materials for tissue engineered meniscus. However, there is no material that can completely simulate the natural meniscus, and further research of scaffold materials is still needed.
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Objective: To review the literature on the research status of vascularization of tissue engineered peripheral nerve so as to provide the theoretical basis for the vascularization of tissue engineered peripheral nerve. Methods: The literature related to the vascularization of peripheral nerve tissue engineering in recent years was reviewed and summarized according to the five aspects of promoting vascularization: local microenvironment and blood supply characteristics of peripheral nerve regeneration, scaffold material modification, seed cells, autologous vascular bundle implantation, and pro-vascular factors. Results: Tissue engineered peripheral nerve has brought a new hope for the repair of peripheral nerve injury, but the repair effect of large nerve defects is not good, which is mainly related to the degree of vascularization of the nerve grafts. So it is particularly important to promote the early vascularization of tissue engineered peripheral nerve. Previous studies have mainly focused on the four aspects of scaffold material modification, seed cells, autologous vascular bundle implantation, and angiogenesis related factors. Recent studies show that the combination of the above two or more factors in the tissue engineered peripheral nerves can better promote the vascularization of tissue engineered peripheral nerves. Conclusion: Promoting early vascularization of tissue engineered peripheral nerves can provide timely nutritional support for seed cells on the scaffold, promote axon growth and nerve regeneration, and facilitate the repair of large peripheral nerve defects in clinical practice.