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BACKGROUND:Metal ions play an important role in the human body.With the progress of material synthesis and processing technology,a variety of metal ions that can be used in bone tissue engineering have been developed,such as magnesium(Mg2+),zinc(Zn2+),manganese(Mn2+),strontium(Sr2+),and copper(Cu2+). OBJECTIVE:To summarize the research progress and development direction of metal ions in bone tissue engineering. METHODS:The literature collected by CNKI,PubMed and WanFang databases from 2014 to 2022 was retrieved.The Chinese and English key words were"metal ions,bone tissue engineering,osteogenic activity,magnesium ions,zinc ions,manganese ions,strontium ions,copper ions,calcium ions,lithium ions,cobalt ions". RESULTS AND CONCLUSION:Different metal ions will be released to varying degrees after the materials are implanted into the body,which can change the tissue microenvironment,thus improving the ability of materials to form blood vessels and bones.Compared with growth factors,metal ions are easier to control the release rate,have lower cost,and can also improve the mechanical properties of implant materials.The application of metal ions in bone tissue engineering is full of prospects.Although some metal ions can already be used to treat bone defects,the mechanism of action of many metal ions in the human body is not completely clear,and the application effect is a lack of clinical experiment verification.Further exploration is needed before clinical application.
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BACKGROUND:With the right bio-inks,3D printing can be used to create replacements for human tissues and organs that work inside the body.In recent years,3D printing technology has developed rapidly and has great application potential in regenerative medicine. OBJECTIVE:To introduce the types of bio-inks for 3D printing,and review the classification,application,advantages and disadvantages of bio-inks,as well as the future vision. METHODS:With"3D printing,biological ink,tissue engineering,hydrogel,synthetic material,cytoactive factor"as search terms,relevant articles published on PubMed and CNKI databases from 2000 to 2022 were searched by computer and finally 83 articles were included for review. RESULTS AND CONCLUSION:3D bioprinting technology has developed rapidly over the past few decades and has received great attention in various fields,including tissue engineering and biomedicine.Compared with the limitations of traditional biological scaffold manufacturing methods in terms of function and structure,3D printing can better simulate the complex structure of biological tissues and has appropriate mechanical,rheological and biological characteristics.Bio-ink is an essential part of 3D printing.Bioscaffolds produced by printing bio-ink prepared by biological materials have great scientific potential and clinical significance in tissue repair and regenerative medicine.The research of the materials itself is also getting more and more attention from experts.Bio-inks for 3D printing come in a variety of materials,from natural to synthetic,to aggregations of cells that do not require any additional biomaterials,and their usefulness in practical use varies.In the future,more and more bio-inks will be developed for tissue engineering.It is necessary to analyze the printability of bio-inks through sufficient experimental simulation and equipment testing to meet the actual medical needs.
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BACKGROUND:Intra-articular injection played an important role in the treatment of osteoarthritis and has more options with the development of novel drug delivery systems.The cartilage targeting function is aimed at the adhesion or retention of drugs in the cartilage layer to form a drug bank to achieve slow release and precise drug delivery. OBJECTIVE:To review various cartilage targeting biomaterials and their characteristics in the treatment of osteoarthritis by articular injection. METHODS:Using the term"osteoarthritis,drug carrier,drug delivery,cartilage targeting,penetrate"as key words,relevant articles were searched in CNKI,WanFang and PubMed databases.According to inclusion and exclusion criteria,67 articles were finally selected for further review. RESULTS AND CONCLUSION:The research on cartilage-targeting biomaterials is mainly divided into two directions.One is the combination of electrostatic interaction,such as the combination of positively charged biomaterials and negatively charged polysaccharides in cartilage.This kind of scheme is operable and easy to modify,but limited by the shortcomings of electrostatic interaction itself,it performs badly in advanced osteoarthritis.Another one is the specific binding of various components in cartilage which is strong and reliable,and related biomaterials have excellent performance in advanced osteoarthritis,which is an important direction for future cartilage-targeted therapy.
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BACKGROUND:In recent years,with the development of biological scaffold materials and bioprinting technology,tissue-engineered bone has become a research hotspot in bone defect repair. OBJECTIVE:To summarize the current treatment methods for bone defects,summarize the biomaterials and bioprinting technology for preparing tissue-engineered bone scaffolds,and explore the application of biomaterials and printing technology in tissue engineering and the current challenges. METHODS:Search terms were"bone defect,tissue engineering,biomaterials,3D printing technology,4D printing technology,bioprinting,biological scaffold,bone repair"in Chinese and English.Relevant documents published from January 1,2009 to December 1,2022 were retrieved on CNKI,PubMed and Web of Science databases.After being screened by the first author,high-quality references were added.A total of 93 articles were included for review. RESULTS AND CONCLUSION:The main treatment methods for bone defects include bone transplantation,membrane-guided regeneration,gene therapy,bone tissue engineering,etc.The best treatment method is still uncertain.Bone tissue engineering technology is a new technology for the treatment of bone defects.It has become the focus of current research by constructing three-dimensional structures that can promote the proliferation and differentiation of osteoblasts and enhance the ability of bone formation.Biological scaffold materials are diverse,with their characteristics,advantages and disadvantages.A single biological material cannot meet the demand for tissue-engineered bone for the scaffold.Usually,multiple materials are combined to complement each other,which is to meet the demand for mechanical properties while taking into account the biological properties of the scaffold.Bioprinting technology can adjust the pore of the scaffold,build a complex spatial structure,and is more conducive to cell adhesion,proliferation and differentiation.The emerging 4D printing technology introduces"time"as the fourth dimension to make the prepared scaffold dynamic.With the synchronous development of smart materials,4D printing technology provides the possibility of efficient repair of bone defects in the future.
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BACKGROUND:In recent years,the treatment of anterior cruciate ligament injury has become more and more mature.However,there are still disputes about the timing of surgery,the choice of surgical methods,the choice of grafts,and the methods to promote graft healing after anterior cruciate ligament injury. OBJECTIVE:To summarize the latest research progress of surgical timing,surgical methods,graft selection and methods to promote graft healing after anterior cruciate ligament injury,and to find new treatment directions for anterior cruciate ligament injury. METHODS:Relevant articles concerning anterior cruciate ligament injury were retrieved from PubMed,CNKI,WanFang Date,VIP,SinoMed,ScienceDirect,Springer and Cochrane Library.After the screening,72 related articles were finally included. RESULTS AND CONCLUSION:(1)Surgical timing:Compared with delayed anterior cruciate ligament reconstruction,early reconstruction can reduce meniscus injury,elevate quality of life,and improve functional recovery.However,it is still uncertain whether the different operation timing will accelerate cartilage injury.(2)Surgical methods:Arthroscopic anterior cruciate ligament reconstruction is a common surgical method for anterior cruciate ligament injury.Dynamic internal stabilization repair of anterior cruciate ligament can bring similar results to traditional anterior cruciate ligament reconstruction in short-term and long-term effects.(3)Graft selection:Autogenous hamstring tendon is the first choice of anterior cruciate ligament graft,while bone-patellar tendon-bone grafts and allografts are the secondary choices.(4)Among the methods to promote graft healing,suture band strengthening can increase knee joint stability and ensure graft healing.Stem cells promote the tendon-bone healing of grafts through anti-inflammatory action,angiogenesis,inhibition of osteolysis and promotion of chondrocyte differentiation.Preserving the residual end of the anterior cruciate ligament can maintain the stability of the knee joint,promote the recovery of proprioception,and provide a prerequisite for the healing of the graft.The effectiveness of platelet-rich plasma in promoting graft healing remains to be discussed.However,biomaterials,gene therapy,stem cell application and other methods to promote tendon healing remain in the stage of molecular and animal researches.Clinical transformation is also needed in the future.
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BACKGROUND:Hydroxyapatite is the main inorganic component of bone tissue.The polymer has the structure and function of a biomimetic extracellular matrix.The composites of hydroxyapatite and polymer have been widely studied. OBJECTIVE:To summarize the research status of hydroxyapatite composite polymer materials for bone tissue repair. METHODS:The articles collected in PubMed,Web of Science,CNKI and WanFang databases were searched from January 2010 to April 2023.The Chinese and English search terms were"hydroxyapatite,polymer,composites,degradability,bone defect,bone repair".Finally,75 articles were included for review. RESULTS AND CONCLUSION:Polymers often used in composite with hydroxyapatite for bone tissue repair include natural polymers(collagen,chitosan,alginate,serine protein,cellulose,hyaluronic acid,and polyhydroxybutyrate)and synthetic polymers[polylactic acid,polylactic acid-hydroxyacetic acid copolymer,poly(has-lactide),poly(amino acid)and poly(vinyl alcohol)].The mechanical properties and osteoinductivity of hydroxyapatite/polymer composites were improved compared with pure hydroxyapatite.Hydroxyapatite composite with polymers can be made into porous scaffolds,hydrogels,and coatings for bone repair.Hydroxyapatite/polymer composites can accelerate bone reconstruction with a slow release of loaded drugs and cytokines due to their bionic extracellular matrix structure and function.Based on the diversity of causes of bone defects and the fact that bone repair is a complex continuous process involving multiple biological factors and proteins,repair materials with mechanical properties matching bone tissue,degradation processes synchronized with bone repair,and efficient osteogenesis and vascularization need to be further investigated.
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BACKGROUND:The remediation and treatment of bone defects present considerable challenges,with a variety of clinical intervention strategies available.One such approach,the Masquelet technique,has demonstrated high rates of success and reliable outcomes and is currently employed in clinical practice.However,the underlying mechanisms of this technique remain incompletely understood,and certain challenges persist in its clinical application,indicating that this technique is not yet fully mature. OBJECTIVE:To compile and categorize the biomaterials currently employed in research aimed at improving the Masquelet technique,in order to provide insights and references for the further development of this technique. METHODS:A literature search of the China National Knowledge Infrastructure and PubMed databases was conducted,spanning publications from January 2013 to November 2022.The search terms used included"Masquelet technique;induced membrane technique;induced membrane;biomaterial;bone defect"in both Chinese and English.A total of 58 articles meeting the inclusion criteria were reviewed. RESULTS AND CONCLUSION:(1)The emergence and continual development of the Masquelet technique provide a therapeutic strategy for treating bone defects.Some researchers are focusing on developing superior spacer materials,autograft substitutes,and membrane materials that mimic the properties of the induced membrane,to simplify the two-stage procedure,shorten treatment duration,and reduce patient distress.(2)Calcium sulfate,silicone,poly(lactic-co-glycolic acid),and polypropylene can replace polymethylmethacrylate bone cement to form induced membranes in animal experiments or clinical applications,each with their advantages.Contrary to expectations,common materials such as titanium and polyvinyl alcohol sponge cannot replace polymethylmethacrylate bone cement.(3)Autograft substitutes are diverse,with allograft bone,β-tricalcium phosphate,absorbable gelatin sponge,α-calcium sulfate hemihydrate,bioactive glass,titanium,and tantalum demonstrating their ability to reduce the quantity of autologous cancellous bone graft required in the second stage of the procedure.Among them,allograft bone,β-tricalcium phosphate,bioactive glass,titanium and tantalum can replace autogenous bone as grafts,and other materials need to be mixed with autogenous bone,in both clinical and fundamental experiments.(4)Biomimetic-induced membranes,human amnion,human decellularized dermis,polytetrafluoroethylene,and even autogenous cortical bone have been shown to possess properties similar to the induced membrane.(5)Most of the application and research of biomaterials in this technology still exist in the stage of basic research and have not been applied in clinical practice or popularized on a large scale,but the above materials can provide more sufficient theoretical basis and new ideas for the exploration of Masquelet technical mechanism,the improvement of surgical methods and clinical application.
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BACKGROUND:Nanostructure modification of pure titanium surface is a hot research field of titanium implant surface treatment. OBJECTIVE:To evaluate the effect of nano-modified titanium surface treated with alkali heat treatment on early adhesion and growth of osteoblasts. METHODS:Four-grade pure titanium sheets with a diameter of 15 mm and a thickness of 1.5 mm were taken and processed in three groups:the smooth treatment group was polished step by step with 250 mesh,800 mesh,and 1 500 mesh silicon carbide sandpaper.In the sandblasting group,the smoothed titanium sheet was sandblasted with 100 μm Al2O3 particles at 0.45 MPa pressure,and then the acid etching was carried out.In the alkali heat treatment group,the smoothed titanium sheet was placed in the reactor,immersed in 10 mol/L NaOH solution,and heated in the oven at 100 ℃for 12 hours.The surface morphology,roughness,and hydrophilicity of three groups of titanium sheets were measured.MG63 osteoblasts were inoculated on the surface of three groups of titanium tablets,and the adhesion of the cells was observed by immunofluorescence staining. RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that the surface of titanium sheets in the smooth treatment group had uniform scratches;the surface of titanium sheets in the sandblasting group was uneven,and the surface of titanium sheets in the alkali heat treatment group had uniform nanoscale three-dimensional pore morphology.The roughness value of the titanium sheets in sandblasting and alkali heat treatment groups was higher than that in the smooth treatment group(P<0.05),and the water contact angle was lower than that in the smooth treatment group(P<0.05).(2)Immunofluorescence staining after 3 and 6 hours of inoculation of MG63 cells showed that the number of adhesion cells on the surface of the titanium sheet in the sandblasting group and alkali heat treatment group was higher than that in the smooth treatment group(P<0.05).Immunofluorescence staining 12 hours after inoculation showed that compared with the smooth treatment group,the actin skeleton of cells on the surface of titanium sheets in the sandblasting group and alkali heat treatment group was more extended,and most cells extended stronger pseudopodia,which was conducive to subsequent intercellular signal transduction and intercellular interaction.(3)The results showed that the nanostructures with certain biological activity could be prepared on the surface of a titanium sheet by alkali heat treatment,which was conducive to the early adhesion of osteoblasts.
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BACKGROUND:Conductive biomaterials are considered potential candidates for transmitting electrical signals for myocardial repair.Combining cell-based or cell-free strategies with conductive biomaterials to replenish cardiomyocytes and/or restore electrical signaling pathways is a promising approach for cardiac repair. OBJECTIVE:To evaluate the effect of polypyrrole-chitosan conductive composite hydrogel on cardiac function in rats with myocardial ischemia-reperfusion injury. METHODS:The polypyrrole-chitosan conductive composite hydrogel was prepared by chemical oxidative polymerization.The micromorphology,biocompatibility and conductivity of the hydrogels were characterized.Thirty adult SD rats were selected to establish a myocardial ischemia-reperfusion injury model by clamping the left anterior descending branch of the heart and then releasing it.After 21 days of modeling,the rats were divided into three groups by the random number table method:Normal saline was injected into the left ventricular infarction area and infarction margin area in the blank group.Chitosan hydrogel was injected into the left ventricular infarction area and infarction margin area in the ordinary hydrogel group.The polypyrrole-chitosan conductive composite hydrogel was injected into the left ventricular infarction area and infarction margin area,with 10 rats in each group.The corresponding time points after modeling were set,and cardiac mechanical function(echocardiogram,pressure-volume analysis),cardiac electrophysiology(electrocardiogram,programmed electrical stimulation,optical mapping technology,microelectrode array technology,eight-lead electrocardiogram,and electrical resistivity of the scar area)and cardiac histology were detected. RESULTS AND CONCLUSION:(1)There were a lot of pores on the surface of the conductive composite hydrogel,and the conductivity was(3.19±0.03)×10-3 mS/cm,which had good biocompatibility co-cultured with smooth muscle cells.(2)After 105 days of modeling,echocardiogram and pressure-volume analysis showed that compared with the blank group and the ordinary hydrogel group,the conductive composite hydrogel could significantly improve the contractile function of the heart of rats with myocardial ischemia-reperfusion injury.The results of electrocardiogram,programmed electrical stimulation,optical mapping technology,microelectrode array technology,eight-lead electrocardiogram,and electrical resistivity of the scar area examination at 105 days after modeling displayed that,compared with the blank group and the ordinary hydrogel group,the conductive composite hydrogel could significantly improve the electrical conduction function of the heart of rats with myocardial ischemia-reperfusion injury and reduce the occurrence of arrhythmia.Masson staining of heart tissue at 105 days after modeling exhibited that there were different degrees of fibrosis in the myocardial infarction area of the three groups.Compared with the normal saline group and the ordinary hydrogel group,the conductive hydrogel group had more normal myocardial tissue and less fibrosis in the myocardial infarction area.(3)The results verify that polypyrrole-chitosan conductive composite hydrogel may promote the repair of infarcted heart after ischemia-reperfusion injury by increasing the electrical conduction velocity of infarct scar area tissue,increasing scar thickness,enhancing synchronous cardiac contraction,and reducing damaged tissue.
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BACKGROUND:With the increasing number of tendon transplantation surgeries for tendon injuries,the demand for tendon tissue engineering scaffolds is increasing.Research has found that good pore size and porosity of implants contribute to tissue healing. OBJECTIVE:To review the types of materials currently published for tendon tissue engineering scaffolds and investigate the correlation between various tendon tissue engineering scaffold materials and pores. METHODS:Articles were retrieved on PubMed,Embase,and Web of Science databases,using keywords"tendon"or"ligament"and"tissue scaffold"as well as"porosity"or"permeability".A total of 84 articles meeting the criteria were included to summarize,discuss and anticipate future development directions. RESULTS AND CONCLUSION:The materials used in the research of tendon tissue engineering are mainly divided into two categories:natural tendon scaffold materials and artificial synthetic tendon scaffold materials.Natural scaffold materials include autologous tendons,allogeneic tendons,and xenogeneic tendons.Autogenous tendons and allogeneic tendons have been used in clinical practice for many years.During the preparation of allogeneic tendons and animal experiments,it was found that the process of acellular disinfection resulted in an increase in the pore size and porosity of both types of tendons,but the specific reasons and mechanisms have not been further studied.There are many types of artificial tendon scaffold materials currently being studied,among which artificial ligament products such as Leeds Keio and LARS(Ligament Advanced Reinforcement System)are still in use in some countries.Other materials have not been promoted in clinical practice due to immature technology and other issues.The pores and porosity of artificial tendon scaffold materials also show different trends due to their different materials and preparation techniques.
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BACKGROUND:Nanocomposite hydrogel has great research prospects and application potential in the treatment of osteoarthritis. OBJECTIVE:To review the research progress of nanocomposite hydrogel in osteoarthritis and cartilage repair. METHODS:Databases such as CNKI and PubMed were searched.The English key words were"nanocomposite hydrogel,nanogel,osteoarthritis,cartage,physical encapsulation,electrostatic interaction,covalent crosslinking",and the Chinese key words were"nanocomposite hydrogel,nanogel,osteoarthritis,cartage,physical encapsulation,physical encapsulation,electrostatic effect,covalent cross-linking".After an initial screening of all articles based on inclusion and exclusion criteria,71 articles with high correlation were retained for review. RESULTS AND CONCLUSION:In cell or animal experiments,nanocomposite hydrogel has the effect of improving osteoarthritis.Nanocomposite hydrogel can promote cartilage repair,improve the internal environment of osteoarthritis,and achieve the therapeutic purpose of osteoarthritis by improving the mechanical environment between joints,carrying targeted drugs,and promoting the chondrogenesis of seed cells.At present,the research of nanocomposite hydrogel in osteoarthritis disease still has a huge space to play.It is expected to open up a new way for the clinical treatment of osteoarthritis by continuing to deepen the research of material preparation and actively carrying out cell and animal experiments.
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BACKGROUND:The study of the physical properties of scaffolds has always been a hot topic in the field of tissue engineering research.However,for vascular stimulating scaffolds,in addition to meeting the basic performance of the scaffold,other methods are also needed to promote the regeneration of blood vessels within the scaffold,in order to achieve the ultimate goal of repairing bone tissue. OBJECTIVE:A visualization analysis was carried out on the literature published in and outside China on scaffold stimulation for bone tissue engineering,to explore the research hotspots and research status in this field,and to provide a reference for subsequent studies. METHODS:Using the CNKI database and Web of Science core database as retrieval databases,the relevant literature on vascular scaffolds for bone tissue engineering was retrieved.The literature that did not conform to the research object was removed.The obtained data were imported into CiteSpace 6.1.R2 software.Visualization analysis was performed on authors,national institutions,and keywords in the research field. RESULTS AND CONCLUSION:(1)China,the United States,and Germany were the top three countries with the most articles on scaffold stimulation for bone tissue engineering.(2)The top 3 institutions in the CNKI database were Southern Medical University,Huazhong University of Science and Technology,and Donghua University.In the core database of Web of Science,Shanghai Jiao Tong University,Sichuan University and Chinese Academy of Sciences ranked the top 3 in terms of the number of institutional publications.(3)The top 3 keywords in the CNKI database were"tissue engineering,vascularization,angiogenesis".The top 3 keywords in the Web of Science core database were"mesenchymal stem cell,scaffold,vascularization".(4)Through the analysis of co-citation and highly cited references,the main concerns were as follows:vascularization strategies:scaffold design,angiogenic factor delivery,in vitro co-culture,and in vivo pre-vascularization.Technology:3D printing,electrospinning,vascular transplantation,vascular fusion.Mechanisms:immune regulation and macrophages,drug/growth factor delivery,the relationship between endothelial cells and osteoblasts,the paracrine relationship between bone cells and endothelial cells,signaling molecular pathways,angiogenesis,and anti-angiogenesis molecules.(5)The researches concerning vascular stimulating scaffolds in bone tissue engineering in and outside China attach great importance to the application of stem cells and 3D printing technology.Current research focuses on biological 3D printing technology,scaffold modification methods,and the development and application of intelligent biomaterials based on bone repair mechanisms.
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BACKGROUND:Electrospun porous nanofiber exhibits excellent properties and designability.It is an effective way to control the release of traditional Chinese medicine and improve the bioavailability to design an advanced drug delivery system,which has a broad application prospect. OBJECTIVE:To review the construction methods of the electrospinning drug delivery system of traditional Chinese medicine and its related research progress in the medical field. METHODS:The literature search was performed in CNKI,PubMed,and Web of Science databases with the search terms"electrospinning,traditional Chinese medicine,drug carrier,drug delivery system,tissue engineering,dressing"in both English and Chinese for articles published from 2013 to 2023.Finally,62 articles were included in this review. RESULTS AND CONCLUSION:(1)The key elements of the electrospinning drug delivery system of Chinese medicine preparation are substrate material,traditional Chinese medicine composition,and drug loading method.(2)The preparation of the electrospinning drug delivery system of Chinese medicine can be carried out according to the application scenario and therapeutic purpose.Firstly,the types of Chinese medicine are selected,then the polymer matrix and solution suitable for them are selected,and finally,the fiber structure is designed according to the drug release requirements and the appropriate drug loading method is adopted.(3)At present,the medicinal agents used are mainly plant Chinese medicine,and there is a lack of systematic research on animal and mineral Chinese medicine.(4)Blended drug loading is the most studied and applied drug loading method,and its drug release characteristics and adaptation scenarios are constantly expanded by optimizing the physicochemical properties of the solution and selecting the diversity of loaded substances.Multilayer fibers with different compositions and properties can be prepared by coaxial,multi-axis,and sequential electrospinning methods,which have broad development prospects.(5)The early application of the electrospinning drug delivery system of Chinese medicine focused on medical dressings according to the antibacterial and hemostatic functions.In recent years,it has been studied in the field of tissue engineering because some components of traditional Chinese medicine can promote cell adhesion,proliferation,and differentiation.(6)At present,the research mainly focuses on the characterization and optimization of loading materials,processes,physicochemical properties,and biological properties,but the research on the mechanism is less.Its clinical application has not been widespread;the adverse reactions in vivo and the interaction between its degradation behavior and drug release behavior are still unknown.(7)Future studies need to consider:We should expand the application of Chinese medicine by improving the physicochemical properties and increasing the purification of Chinese medicine extracts.We need to comprehensively study the therapeutic effects and application mechanisms of Chinese medicine,and clarify the interaction of degradation behavior and drug release behavior,to achieve a more perfect combination and application of Chinese medicine and electrospinning nanofibers under a more accurate mechanism.
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BACKGROUND:Mesenchymal stem cells are pluripotent stromal cells isolated from a variety of tissues,which can differentiate into osteoblasts under certain conditions.Photobiomodulation,as an external stimulus,can promote osteogenic differentiation combined with other inducers or alone,providing new ideas for solving a series of bone diseases. OBJECTIVE:To review the relevant literature and mechanisms of photobiomodulation-induced osteogenic differentiation of mesenchymal stem cells,which will lay a theoretical foundation for bone tissue engineering using mesenchymal stem cells as seed cells and may offer some suggestions for future studies. METHODS:Relevant articles were searched on CNKI,PubMed and Wed of Science databases with Chinese search terms of"photobiomodulation,low power laser,low level laser,light-emitting diode,mesenchymal stem cells,osteogenic differentiation,biomaterials"and English search terms of"photobiomodulation,low level laser(light),light-emitting diode(LED),mesenchymal stem cell,osteogenic differentiation,biomaterials".Finally,88 articles were included for analysis. RESULTS AND CONCLUSION:(1)Photobiomodulation represented by low level laser and diode laser has a positive effect on promoting the proliferation and differentiation of mesenchymal stem cells.(2)Photobiomodulation can induce osteogenic differentiation of mesenchymal stem cells,whose feasibility has been verified in cell and animal experiments.On one hand,photobiomodulation can promote the expansion and differentiation of stem cells in vitro by activating related signaling pathways and up-regulating the expression of osteogenic molecules.On the other hand,photobiomodulation can improve the survival rate of stem cells in vivo,promote homing effect and shorten the healing time of bone defects after stem cells are injected into the body.However,photobiomodulation has a biphasic dose effect,whose laser parameters,experimental environment,cell type and other factors in various studies are different,making the research results lack consistency and difficult to apply in the clinic.(3)Combined with biological materials,other physical factors and drugs,photobiomodulation can also accelerate osteogenic differentiation.(4)In conclusion,photobiomodulation has been used increasingly widely in the medical field with its advantages of non-invasive,efficient and less-side reactions,and its role in bone tissue engineering has gradually become prominent,which provides a new method for the treatment of bone defects and related diseases.Further exploration should be focused on the standardized treatment parameters of photobiomodulation.
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BACKGROUND:Spinal cord injury not only causes serious physical and psychological injuries to patients but also brings a heavy economic burden to society.Spinal cord injury is initially triggered by mechanical trauma,followed by secondary injuries,and as the disease progresses,a glial scar develops. OBJECTIVE:To summarize the pathological process of spinal cord injury and strategies for stem cell transplantation to repair spinal cord injury,aiming to provide the best protocol for treating spinal cord injury. METHODS:Computer search was used to search PubMed and CNKI databases.Chinese search terms were"stem cell transplantation,spinal cord injury".English search terms were"stem cell,spinal cord injury,spinal cord,mesenchymal stem cells,neural stem cells,pathophysiology,clinical trial,primary injury,secondary injury".The literature was screened according to the inclusion and exclusion criteria.Finally,91 articles were included for review analysis. RESULTS AND CONCLUSION:(1)The strategies for repairing spinal cord injury through stem cell transplantation can be divided into exogenous stem cell transplantation and endogenous stem cell transplantation.The exogenous stem cell transplantation strategy for the treatment of spinal cord injury is divided into four kinds:injecting stem cells into the site of injury;transplantation of biomaterials loaded with stem cells;fetal tissue transplantation;transplantation of engineered neural network tissue or spinal cord-like tissue.(2)Compared with a single treatment method,combination therapy can more effectively promote nerve regeneration and spinal cord function recovery.(3)Microenvironment regulating the injury site,magnetic stimulation,electrical stimulation,epidural oscillating electric field stimulation,transcription factor overexpression and rehabilitation therapy can be combined with stem cell transplantation for combination therapy,thereby promoting the recovery of spinal cord function.
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BACKGROUND:Mesenchymal stem cells have great potential in the treatment of ischemia-reperfusion injury of skin flaps.However,their defects and the decline of their role in the treatment of ischemia-reperfusion injury of skin flaps restrict their wide application. OBJECTIVE:To review the strategies for improving the treatment of ischemia-reperfusion injury of skin flaps with mesenchymal stem cells,and provide a reference for its further theoretical research and clinical application. METHODS:Relevant documents included in CNKI,WanFang and PubMed were searched.The Chinese and English search terms were"mesenchymal stem cell,ischemia-reperfusion adjustment of skin flap,mesenchymal stem cells,stem cells,skin flap,ischemia-reperfusion injury,pretreatment,gene modification,biomaterial packaging,joint application".The relevant documents since 2007 were retrieved,and the documents with little relationship between the research content and the article theme,poor quality and outdated content were eliminated through reading the article,and finally 75 documents were included for summary. RESULTS AND CONCLUSION:(1)Mesenchymal stem cells can inhibit inflammatory reactions,resist oxidative stress and induce angiogenesis,which has great potential in the treatment of skin flap ischemia-reperfusion injury.(2)Although mesenchymal stem cells have shown great potential in the treatment of skin flap ischemia-reperfusion injury,their shortcomings in treatment have limited their widespread clinical application.Through pre-treatment(cytokines,hypoxia,drugs,and other pre-treatment mesenchymal stem cells),gene-modified mesenchymal stem cells,biomaterial encapsulation of mesenchymal stem cells,as well as the combined use of mesenchymal stem cells and other drugs or therapeutic methods,can not only overcome the shortcomings of mesenchymal stem cells in treatment,but also improve their therapeutic effectiveness in skin flap ischemia-reperfusion injury.(3)Therefore,further improving the effectiveness of mesenchymal stem cells in treating skin flap ischemia-reperfusion injury and exploring its therapeutic potential are of great significance for the research of mesenchymal stem cells and the treatment of skin flap ischemia-reperfusion injury.
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BACKGROUND:The treatment of bone defects has always been a pressing clinical challenge for medical practitioners.The use of gelatin methacryloyl for three-dimensional extracellular cultivation offers a promising direction for the treatment of extensive bone defects. OBJECTIVE:To review the research progress of gelatin methacryloyl as a three-dimensional cell culture scaffold in bone tissue engineering,aiming to provide further references for clinical bone defect repair. METHODS:Computerized searches were conducted on the CNKI and PubMed databases for articles published from January 1986 to August 2023.The search terms in Chinese and English were"bone defect,bone tissue engineering,biomaterial scaffold,hydrogel,photocrosslinked hydrogel,gelatin methacryloyl,three-dimensional culture,cell culture"and"bone defect,bone tissue engineering,biomaterial scaffold,hydrogel,gelatin methacryloyl,three-dimensional culture,cell culture",respectively.Finally,68 articles were included for review and analysis. RESULTS AND CONCLUSION:(1)When compared to two-dimensional culture techniques,three-dimensional culture can construct a three-dimensional space under aseptic conditions,more effectively simulating the in vivo environment.It provides cells with the appropriate temperature,pH,and sufficient nutrients,allowing cells to grow and proliferate normally outside the body while maintaining their regular structure and function,offering unique advantages.(2)In the realm of bone tissue engineering,hydrogels stand out as the preferred choice for biomaterial scaffolds.Their excellent biocompatibility,degradability,and inherent three-dimensional network structure make them invaluable in bone regeneration studies.(3)The physical and biological properties of gelatin methacryloyl are influenced by factors such as concentration,light exposure duration,type of photoinitiator,and the overall reaction system.These properties can affect cell adhesion,growth,and proliferation,and even the morphology and function of cells.(4)Gelatin methacryloyl,recognized for its excellent biocompatibility,tunable physical properties,injectability,and photosensitivity,has been extensively used in three-dimensional cell encapsulation,three-dimensional bioprinting,and stereolithography techniques based on digital light processing in three-dimensional cell culture systems.(5)Utilizing a range of composite gelatin methacryloyl in three-dimensional cell culture can significantly promote vascularization and bone regeneration,paving the way for enhanced clinical solutions to bone defects.(6)At present,there is a noticeable gap in standardized guidelines concerning the sources,synthesis methods,and safety of gelatin methacryloyl.It is crucial to intensify research efforts to optimize gelatin methacryloyl's application in the three-dimensional cell culture field.
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BACKGROUND:At present,the treatment of infected bone defects has the problems of long course of disease,poor treatment effect and high cost.The osteogenic effect of personalized bone replacement materials in clinical treatment is limited.Therefore,a 3D-printed bone graft material with both good osteogenic effect and antibacterial effect is urgently needed for clinical treatment. OBJECTIVE:To summarize the research status of 3D-printed scaffolds loaded with antimicrobial agents for the treatment of infected bone defects. METHODS:PubMed,Web of Science,Elsevier,and CNKI databases from January 2010 to June 2022 were searched for related articles.The Chinese search terms were"bone defect,3D printing,scaffold material,antibacterial,animal experiments,in vitro experiments".English search terms were"bone defect,3D printing,scaffold,antibiosis,animal experiment,in vitro".Finally,60 articles were included for review and analysis. RESULTS AND CONCLUSION:The 3D scaffolds made of titanium,magnesium,tantalum and other metals and their alloys have certain osteogenic properties,but do not have antibacterial function.Hydroxyapatite and other bioceramic materials have good biocompatibility and are prone to be degraded,whereas due to the lack of strength,they are usually combined with artificial polymer materials to form composite materials,which respectively mimic the inorganic and organic components in natural bone,and play their respective excellent functions.Antibiotics,silver/copper nanoparticles,antimicrobial peptides,gallium and other antibacterial agents play an antibacterial role by destroying bacterial cell membrane,producing reactive oxygen species to interfere with bacterial DNA replication,inhibiting iron absorption and other mechanisms.As a result,the 3D-printed scaffold has both antibacterial and osteogenic effects.However,there are still some problems such as drug resistance and difficult to control effective concentrations.3D-printed scaffolds are often loaded with antibacterial agents by loading drug-loaded microspheres on scaffolds,preparing antibacterial coating on the scaffold surface,and participating in joint 3D printing with drugs.The loading mode of antibacterial coating prepared on the scaffold surface is the most widely used,and its antibacterial effect is more stable.Nonetheless,the selection of the most suitable loading mode for antibacterial agents needs to be further discussed and summarized.It is a future research prospect to optimize the mechanical properties of composite scaffolds and prepare biomimetic bone scaffolds so that the degradation rate is consistent with the bone reconstruction rate in infected bone defects.The ideal antibacterial agents may play a role through a variety of antibacterial mechanisms,thus being expected to play a good antibacterial effect through low antibacterial concentration,which should be a hot spot of anti-bone infection research.After loading antibacterial agents on the surface of the scaffold,antibacterial agents can"intelligently"react to the local microenvironment,achieving controlled release,and regulating the osteogenesis,vascularization and immune response of the microenvironment,which is the focus of current research.
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The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.
El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.
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Despite exciting achievements with some malignancies, immunotherapy for hypoimmunogenic cancers, especially glioblastoma (GBM), remains a formidable clinical challenge. Poor immunogenicity and deficient immune infiltrates are two major limitations to an effective cancer-specific immune response. Herein, we propose that an injectable signal-amplifying nanocomposite/hydrogel system consisting of granulocyte-macrophage colony-stimulating factor and imiquimod-loaded antigen-capturing nanoparticles can simultaneously amplify the chemotactic signal of antigen-presenting cells and the "danger" signal of GBM. We demonstrated the feasibility of this strategy in two scenarios of GBM. In the first scenario, we showed that this simultaneous amplification system, in conjunction with local chemotherapy, enhanced both the immunogenicity and immune infiltrates in a recurrent GBM model; thus, ultimately making a cold GBM hot and suppressing postoperative relapse. Encouraged by excellent efficacy, we further exploited this signal-amplifying system to improve the efficiency of vaccine lysate in the treatment of refractory multiple GBM, a disease with limited clinical treatment options. In general, this biomaterial-based immune signal amplification system represents a unique approach to restore GBM-specific immunity and may provide a beneficial preliminary treatment for other clinically refractory malignancies.