Polycaprolactone(PCL)scaffolds that are produced through additive manufacturing are one of the most researched bone tissue engineering structures in the field.Due to the intrinsic limitations of PCL,carbon nanomateria...Polycaprolactone(PCL)scaffolds that are produced through additive manufacturing are one of the most researched bone tissue engineering structures in the field.Due to the intrinsic limitations of PCL,carbon nanomaterials are often investigated to reinforce the PCL scaffolds.Despite several studies that have been conducted on carbon nanomaterials,such as graphene(G)and graphene oxide(GO),certain challenges remain in terms of the precise design of the biological and nonbiological properties of the scaffolds.This paper addresses this limitation by investigating both the nonbiological(element composition,surface,degradation,and thermal and mechanical properties)and biological characteristics of carbon nanomaterial-reinforced PCL scaffolds for bone tissue engineering applications.Results showed that the incorporation of G and GO increased surface properties(reduced modulus and wettability),material crystallinity,crystallization temperature,and degradation rate.However,the variations in compressive modulus,strength,surface hardness,and cell metabolic activity strongly depended on the type of reinforcement.Finally,a series of phenomenological models were developed based on experimental results to describe the variations of scaffold’s weight,fiber diameter,porosity,and mechanical properties as functions of degradation time and carbon nanomaterial concentrations.The results presented in this paper enable the design of three-dimensional(3D)bone scaffolds with tuned properties by adjusting the type and concentration of different functional fillers.展开更多
Bone is a complex but orderly mineralized tissue with hydroxyapatite(HA)as the inorganic phase and collagen as the organic phase.Inspired by natural bone tissues,HA-mineralized hydrogels have been widely designed and ...Bone is a complex but orderly mineralized tissue with hydroxyapatite(HA)as the inorganic phase and collagen as the organic phase.Inspired by natural bone tissues,HA-mineralized hydrogels have been widely designed and used in bone tissue engineering.HA is majorly utilized for the treatment of bone defects because of its excellent osteoconduction and bone inductivity.Hydrogel is a three-dimensional hydrophilic network structure with similar properties to the extracellular matrix(ECM).The combination of HA and hydrogels produces a new hybrid material that could effectively promote osteointegration and accelerate the healing of bone defects.In this review,the structure and growth of bone and the common strategies used to prepare HA were briefly introduced.Importantly,we discussed the fabrication of HA mineralized hydrogels from simple blending to in situ mineralization.We hope this review can provide a reference for the development of bone repair hydrogels.展开更多
Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have bee...Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have been recognized for their biocompatibility and biodegradability.However,their susceptibility to rapid corrosion and degradation has garnered notable research interest in bone tissue engineering(BTE),particularly in the development of Mg-incorporated biocomposite scaffolds.These scaffolds gradually release Mg2+,which enhances immunomodulation,osteogenesis,and angiogenesis,thus facilitating effective bone regeneration.This review presents myriad fabrication techniques used to create Mg-incorporated biocomposite scaffolds,including electrospinning,three-dimensional printing,and sol-gel synthesis.Despite these advancements,the application of Mg-incorporated biocomposite scaffolds faces challenges such as controlling the degradation rate of Mg and ensuring mechanical stability.These limitations highlight the necessity for ongoing research aimed at refining fabrication techniques to better regulate the physicochemical and osteogenic properties of scaffolds.This review provides insights into the potential of Mg-incorporated biocomposite scaffolds for BTE and the challenges that need to be addressed for their successful translation into clinical applications.展开更多
Identifying an effective way to promote bone regeneration for patients who suffer from bone defects is urgently demanded.In recent years,mesenchymal stem cells(MSCs)have drawed wide attention in bone regeneration.Besi...Identifying an effective way to promote bone regeneration for patients who suffer from bone defects is urgently demanded.In recent years,mesenchymal stem cells(MSCs)have drawed wide attention in bone regeneration.Besides,several studies have indicated the secretions of MSCs,especially exosomes,play a vital role in bone regeneration process.Exosomes can transfer“cargos”of proteins,RNA,DNA,lipids,to regulate fate of recipient cells by affecting their proliferation,differentiation,migration and gene expression.In this paper,the application of MSCs-derived exosomes in bone tissue engineering is reviewed,and the potential therapeutic role of exosome microRNA in bone regeneration is emphasized.展开更多
A new biomimetic bone tissue engineering scaffold material, nano-HAI PLGA-( PEG-Asp )n composite, was synthesized by a biologically inspired self-assembling approach. A novel biodegradable PLGA- ( PEG-Asp )n cop...A new biomimetic bone tissue engineering scaffold material, nano-HAI PLGA-( PEG-Asp )n composite, was synthesized by a biologically inspired self-assembling approach. A novel biodegradable PLGA- ( PEG-Asp )n copolymer with pendant amine functional groups and enhanced hydrophilicity woo synthesized by bulk ring-opening copolymerization by DL-lactide( DLLA) and glycolide( GA ) with Aspartic acid ( Asp )-Polyethylene glycol(PEG) alt-prepolymer. A Three-dimensional, porous scaffold of the PLGA-( PEG- Asp)n copolymer was fabricated by a solvent casting , particulate leaching process. The scaffold woo then incubated in modified simulated body fluid (naSBF). Growth of HA nanocrystals on the inner pore surfaces of the porous scaffold is confirmed by calcium ion binding analyses, SEM , mass increooe meoourements and quantification of phosphate content within scaffolds. SEM analysis demonstrated the nucleation and growth of a continuous bonelike, low crystalline carbonated HA nanocrystals on the inner pore surfaces of the PLGA- ( PEG-Asp )n scaffolds. The amount of calcium binding, total mass and the mass of phosphate on experimental PLGA- ( PEG-Asp ) n scaffolds at different incubation times in mSBF was significantly greater than that of control PLGA scaffolds. This nano-HA/ PLGA-( PEG- Asp )n composite stunts some features of natural bone both in main composition and hierarchical microstrueture. The Asp- PEG alt-prepolymer modified PleA copolymer provide a controllable high surface density and distribution of anionic functional groups which would enhance nucleation and growth of bonelike mineral following exposure to mSBF. This biomimetic treatment provides a simple method for surface functionalization and sabsequent mineral nucleation and self-oosembling on bodegradable polymer scaffolds for tissue engineering.展开更多
Bone tissue engineering represents one of the most challenging emergent fields for scientists and clinicians.Current failures of autografts and allografts in many pathological conditions have prompted researchers to f...Bone tissue engineering represents one of the most challenging emergent fields for scientists and clinicians.Current failures of autografts and allografts in many pathological conditions have prompted researchers to find new biomaterials able to promote bone repair or regeneration with specific characteristics of biocompatibility,biodegradability and osteoinductivity.Recent advancements for tissue regeneration in bone defects have occurred by following the diamond concept and combining the use of growth factors and mesenchymal stem cells(MSCs).In particular,a more abundant and easily accessible source of MSCs was recently discovered in adipose tissue.These adipose stem cells(ASCs)can be obtained in large quantities with little donor site morbidity or patient discomfort,in contrast to the invasive and painful isolation of bone marrow MSCs.The osteogenic potential of ASCs on scaffolds has been examined in cell cultures and animal models,with only a few cases reporting the use of ASCs for successful reconstruction or accelerated healing of defects of the skull and jaw in patients.Although these reports extend our limited knowledge concerning the use of ASCs for osseous tissue repair and regeneration,the lack of standardization in applied techniques makes the comparison between studies difficult.Additional clinical trials are needed to assess ASC therapy and address potential ethical and safety concerns,which must be resolved to permit application in regenerative medicine.展开更多
Interconnectivity is the key characteristic of bone tissue engineering scaffold modulating cell migration,blood vessels invasion and transport of nutrient and waste.However,efforts and understanding of the interconnec...Interconnectivity is the key characteristic of bone tissue engineering scaffold modulating cell migration,blood vessels invasion and transport of nutrient and waste.However,efforts and understanding of the interconnectivity of porous Mg is limited due to the diverse architectures of pore struts and pore size distribution of Mg scaffold systems.In this work,biomimetic hierarchical porous Mg scaffolds with tailored interconnectivity as well as pore size distribution were prepared by template replication of infiltration casting.Mg scaffold with better interconnectivity showed lower mechanical strength.Enlarging interconnected pores would enhance the interconnectivity of the whole scaffold and reduce the change of ion concentration,pH value and osmolality of the degradation microenvironment due to the lower specific surface area.Nevertheless,the degradation rates of five tested Mg scaffolds were no different because of the same geometry of strut unit.Direct cell culture and evaluation of cell density at both sides of four typical Mg scaffolds indicated that cell migration through hierarchical porous Mg scaffolds could be enhanced by not only bigger interconnected pore size but also larger main pore size.In summary,design of interconnectivity in terms of pore size distribution could regulate mechanical strength,microenvironment in cell culture condition and cell migration potential,and beyond that it shows great potential for personalized therapy which could facilitate the regeneration process.展开更多
BACKGROUND In the medical and dental fields,there is a need for studies of new therapeutic approaches for the treatment of bone defects that cause extensive bone loss.Melatonin may be an important endogenous biologica...BACKGROUND In the medical and dental fields,there is a need for studies of new therapeutic approaches for the treatment of bone defects that cause extensive bone loss.Melatonin may be an important endogenous biological factor for bone remodeling,and growth factors may enhance the repair process.AIM To evaluate the gene expression of cytokines(IL-1β,IL-6,IL-10 and TNF-α),markers of osteoclastogenesis(RANK,RANKL and OPG)and MMPs(MMP-1,MMP-2,MMP-8 and MMP-13)from the treatment of melatonin associated with an osteogenic membrane and rhBMP-2 on the recovery of a bone injury.METHODS Sixty-four rats were used and divided into 9 experimental groups and were formed according to the treatment carried out in the region of the bone lesion,which varied between the combination of 1,10 and 100μmol/L of melatonin.Gene Expression analysis was performed using real time-PCR by reading the concentration of total RNA and reverse transcription.RESULTS There were differences between groups when compared with clot or scaffold control,and improvement with a higher concentration of melatonin or rhBMP-2.The combination melatonin(1μg)with 5μg of rhBMP-2,using the guided bone regeneration technique,demonstrated some effects,albeit mild,on bone repair of critical bone defects.CONCLUSION This indicates that the approach for administering these substances needs to be reassessed,with the goal of ensuring their direct application to the affected area.Therefore,future research must be carried out,seeking to produce materials with these ideal characteristics.展开更多
Peripheral nerve injury(PNI)is a common neurological disorder and complete functional recovery is difficult to achieve.In recent years,bone marrow mesenchymal stem cells(BMSCs)have emerged as ideal seed cells for PNI ...Peripheral nerve injury(PNI)is a common neurological disorder and complete functional recovery is difficult to achieve.In recent years,bone marrow mesenchymal stem cells(BMSCs)have emerged as ideal seed cells for PNI treatment due to their strong differentiation potential and autologous trans-plantation ability.This review aims to summarize the molecular mechanisms by which BMSCs mediate nerve repair in PNI.The key mechanisms discussed include the differentiation of BMSCs into multiple types of nerve cells to promote repair of nerve injury.BMSCs also create a microenvironment suitable for neuronal survival and regeneration through the secretion of neurotrophic factors,extracellular matrix molecules,and adhesion molecules.Additionally,BMSCs release pro-angiogenic factors to promote the formation of new blood vessels.They modulate cytokine expression and regulate macrophage polarization,leading to immunomodulation.Furthermore,BMSCs synthesize and release proteins related to myelin sheath formation and axonal regeneration,thereby promoting neuronal repair and regeneration.Moreover,this review explores methods of applying BMSCs in PNI treatment,including direct cell trans-plantation into the injured neural tissue,implantation of BMSCs into nerve conduits providing support,and the application of genetically modified BMSCs,among others.These findings confirm the potential of BMSCs in treating PNI.However,with the development of this field,it is crucial to address issues related to BMSC therapy,including establishing standards for extracting,identifying,and cultivating BMSCs,as well as selecting application methods for BMSCs in PNI such as direct transplantation,tissue engineering,and genetic engineering.Addressing these issues will help translate current preclinical research results into clinical practice,providing new and effective treatment strategies for patients with PNI.展开更多
AIM: To improve osteogenic differentiation and attachment of cells.METHODS: An electronic search was conducted inPub Med from January 2004 to December 2013. Studies which performed smart modifications on conventional ...AIM: To improve osteogenic differentiation and attachment of cells.METHODS: An electronic search was conducted inPub Med from January 2004 to December 2013. Studies which performed smart modifications on conventional bone scaffold materials were included. Scaffolds with controlled release or encapsulation of bioactive molecules were not included. Experiments which did not investigate response of cells toward the scaffold(cell attachment, proliferation or osteoblastic differentiation) were excluded. RESULTS: Among 1458 studies, 38 met the inclusion and exclusion criteria. The main scaffold varied extensively among the included studies. Smart modifications included addition of growth factors(group Ⅰ-11 studies), extracellular matrix-like molecules(group Ⅱ-13 studies) and nanoparticles(nano-HA)(group Ⅲ-17 studies). In all groups, surface coating was the most commonly applied approach for smart modification of scaffolds. In group I, bone morphogenetic proteins were mainly used as growth factor stabilized on polycaprolactone(PCL). In group Ⅱ, collagen 1 in combination with PCL, hydroxyapatite(HA) and tricalcium phosphate were the most frequent scaffolds used. In the third group, nano-HA with PCL and chitosan were used the most. As variable methods were used, a thorough and comprehensible compare between the results and approaches was unattainable.CONCLUSION: Regarding the variability in methodology of these in vitro studies it was demonstrated that smart modification of scaffolds can improve tissue properties.展开更多
Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone l...Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors(GFs), it makes stem cells the ideal agents for bone regeneration.Furthermore, platelet-rich plasma(PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.展开更多
A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal surface.In this method,reverse engineering software was used to reconstruct the surface from po...A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal surface.In this method,reverse engineering software was used to reconstruct the surface from point cloud data.This method overcomes the limitations of commercially available software packages that prevent them from generating models with complex surfaces used for bone tissue engineering scafolds.Additionally,the fluid feld of the scafolds was simulated through a numerical method based on fnite volume and the cell proliferation performance was evaluated via an in vitro experiment.The cell proliferation and the mass flow evaluated in a bioreactor further verifed the flow feld simulated using computational fluid dynamics.The result of this study illustrates that the pressure value drops rapidly from 0.103 Pa to 0.011 Pa in the y-axis direction and the mass flow is unevenly distributed in the outlets.The mass flow in the side outlets is observed to be approximately 24.3 times higher thanthe bottom.Importantly,although the mean value of wall shear stress is signifcantly more than 0.05 Pa,there is stil a large area with a suitable shear stress below 0.05 Pa where most cells can proliferate well.The result shows that th inlet velocity 0.0075 m/s is suitable for cell proliferation in the scafold.This study provides an insight into the design analysis,and in vitro experiment of a bone tissue engineering scafold.展开更多
Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods C...Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods Cancellous bone were extracted from rabbit femoral head and cut into I-ram-thick and 8-ram-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 με respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase (AKP) and tartrate-resistant acid phosphatase (TRAP) were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. Results After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 με were significantly lower than those in the unstressed bone tissues (all P〈0.05). DNA ladders were seen in the bone tissue under 3000 and 4000με mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 με (all P〈0.05). Conclusions The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteobiasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 με.展开更多
In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongo...In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.展开更多
Fibrous hydroxyapatite ( HA ) wns grown upwards from the crosslinked unsaturated polyphosphoester( UPPE ) which was used us an injectable bone tissue engineering scaffolds. Composition of fibrous HA was determine...Fibrous hydroxyapatite ( HA ) wns grown upwards from the crosslinked unsaturated polyphosphoester( UPPE ) which was used us an injectable bone tissue engineering scaffolds. Composition of fibrous HA was determined by FT- IR, XRD and EDX, which suggested that the fibrous HA was calcium deficient carbonated apatitie with low crystallinity. SEM micrographs indicated that the fibrous HA had a hollow tubing structure and tube wall wus a flakelike assembly. The fibre with poor mechanical property arm with a growth rate about 0. 5 mm/min reached several centimeters in length after 2 hours. The growth was at the tip of the fibre suggested that the procedure of forming fibrous HA was as follows : Co^2+ ions were firstly incorporated into the crosslinked UPPE by dipping in Ca^2+ solution, then supplied through micropores of the material reacted with PO4^3- ions to form α small tuhe , the osmotic pressure or capillary force lead the Ca^2+ continuously gushed oat into the PO4^3- solution, thus fibrous HA was obtained.展开更多
A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macr...A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macro channels' shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200-400 μm. The porosity and connectivity of micro pores became higher with the increase of porogen ratio, while the mechanical properties weakened. The average porosity and compressive strength offl-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 MPa, respectively. The cells' adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds.展开更多
Composite nanofibrous mats consisting of poly( L-lactideco-ε-caprolactone)( PLCL) and collagen type I( COL) were fabricated by electrospinning,and ten times simulated body fluid(10SBF) were employed to mineralize nan...Composite nanofibrous mats consisting of poly( L-lactideco-ε-caprolactone)( PLCL) and collagen type I( COL) were fabricated by electrospinning,and ten times simulated body fluid(10SBF) were employed to mineralize nanofibrous mats. Ballshaped hydroxyapatite( HA) was deposited on the surface of nanofibrous mats in 1. 5 h at room temperature. Human fetal osteoblasts( hFob) were seeded to investigate their proliferation and differentiation on mineralized composite nanofibrous mats. The results showed that hFob grew well on mineralized composite nanofibrous mats and alkaline phosphatase( ALP) activity of hFob on mineralized composite nanofibrous mats at 14 d was much higher than that on untreated nanofibrous mats. Moreover,the expression of osteocalcin of cells on mineralized composite nanofibrous mats was also much higher than those on untreated nanofibrous mats at 7 d and 14 d. This mineralized composite nanofibrous mats may have a great potential for bone tissue engineering.展开更多
To study the osteogenic ability of tissue-engineered bone constructed by compounding zinc-sintered bovine cancellous bone with rabbit marrow stromal cells (MSCs) in vivo,the zinc-sintered bovine cancellous bone of bet...To study the osteogenic ability of tissue-engineered bone constructed by compounding zinc-sintered bovine cancellous bone with rabbit marrow stromal cells (MSCs) in vivo,the zinc-sintered bovine cancellous bone of beta-tricalcium phosphate (TCP) type was prepared by sintering the fresh calf cancellous bone twice and then loading it with zinc-ion.The rabbit MSCs were cultured,induced and seeded onto the zinc-sintered bovine cancellous bones.The tissue-engineered bones were then implanted into the rabbits' back muscles.The newly formed bone tissues were observed by histological methods and the areas of new osseous tissues were measured at the end of the 4th and 8th week.The zinc-sintered bovine cancellous bones alone were implanted on the other side as control.The osteogenic activity of MSCs was identified by alkaline phosphatase (ALP) staining and calcification nod chinalizarin staining.At the end of 4th week,a small amount of new bone tissues was observed.At the end of 8th week,there were many newly formed bone mature tissues.Moreover,the area of the latter was significantly larger than that of the former(P<0.01),while in the control group there was no new bone formation.The tissue-engineered bone,which was constructed by combining zinc-sintered bovine cancellous bone with MSCs,has satisfactory osteogenic capabilities in vivo.展开更多
Biodegradable shape memory polymers( SMPs) are a class of intelligent materials with great potential for imparting biomaterial scaffolds multifunctionality in the field of tissue engineering and regenerative medicine....Biodegradable shape memory polymers( SMPs) are a class of intelligent materials with great potential for imparting biomaterial scaffolds multifunctionality in the field of tissue engineering and regenerative medicine.In this study,the biodegradable SMP poly( D,L-lactide-co-trimethylene carbonate)( PLMC) incorporated with the dexamethasone( Dex),which was a kind of synthetic bone-formation inducing factor,was fabricated into nanofibers via electrospinning.The morphology,constituent,thermal and mechanical properties of the produced Dex / PLMC composite nanofibers were characterized by scanning electron microscopy( SEM), Fourier transform infrared spectroscopy( FTIR), differential scanning calorimetry( DSC),and tensile testing,respectively.Then,ultrasound was employed as a remote stimulus to regulate the Dex releasing behavior from the composite nanofibers.It was found that the generated Dex /PLMC composite nanofibers had a uniform and smooth morphology with a diameter of ca.564 nm.Mechanical testing results showed that incorporation of the Dex gave rise to improved mechanical performance with the tensile strength,Young's modulus and strainat-break increased by 18.2%,20.0% and 64.4%,respectively.DSC data revealed that the glass transition temperature( Tg) of the composite nanofibers, i.e., the thermal transition temperature( Ttrans) for activating shape memory effect, was 39.7 ℃.Moreover, the release kinetics of the encapsulated Dex in the nanofibers could be manipulated by varying the acoustic power and insonation duration.These results suggested that the newly developed Dex / PLMC nanofibers could be a promising drug delivery system for applications in bone tissue engineering( BTE).展开更多
Tissue engineering’s main goal is to regenerate or replace tissues or organs that have been destroyed by disease,injury,or congenital disabilities.Tissue engineering now uses artificial supporting structures called s...Tissue engineering’s main goal is to regenerate or replace tissues or organs that have been destroyed by disease,injury,or congenital disabilities.Tissue engineering now uses artificial supporting structures called scaffolds to restore damaged tissues and organs.These are utilized to attach the right cells and then grow them.Rapid prototyping appears to be the most promising technology due to its high level of precision and control.Bone tissue replacement“scaffolding”is a common theme discussed in this article.The fused deposition technique was used to construct our scaffold,and a polymer called polylactic acids and soybean oil resin were used to construct our samples.The samples were then divided into two groups;the first group was left without immersion in the simulated body fluid and served as a control for comparison.The second group was immersed in the simulated body fluid.The results of the Field Emission Scanning Electron Microscope(FESEM),Energy Dispersive X-ray Spectroscopy(EDX)and X-ray diffraction(XRD)were utilized to interpret the surface attachment to ions,elements,and compounds,giving us a new perspective on scaffold architecture.In this study,an innovative method has been used to print therapeutic scaffold that combines fused deposition three-dimensional printing with ultraviolet curing to create a high-quality biodegradable polymeric scaffold.Finally,the results demonstrate that adding soybean oil resin to the PLA increased ion attachment to the surface while also attracting tricalcium phosphate formation on the surface of the scaffold,which is highly promising in bone tissue replacement.In conclusion,the soybean oil resin,which is new in the field of bone tissue engineering,shows magnificent characteristics and is a good replacement biopolymer that replaces many ceramic and polymeric materials used in this field that have poor morphological characteristics.展开更多
基金The authors wish to acknowledge Engineering and Physical Sciences Research Council(EPSRC)UK for the Global Challenges Research Fund(No.EP/R015139/1)Rosetrees Trust UK&Stoneygate Trust UK for the Enterprise Fellowship(Ref:M874).
文摘Polycaprolactone(PCL)scaffolds that are produced through additive manufacturing are one of the most researched bone tissue engineering structures in the field.Due to the intrinsic limitations of PCL,carbon nanomaterials are often investigated to reinforce the PCL scaffolds.Despite several studies that have been conducted on carbon nanomaterials,such as graphene(G)and graphene oxide(GO),certain challenges remain in terms of the precise design of the biological and nonbiological properties of the scaffolds.This paper addresses this limitation by investigating both the nonbiological(element composition,surface,degradation,and thermal and mechanical properties)and biological characteristics of carbon nanomaterial-reinforced PCL scaffolds for bone tissue engineering applications.Results showed that the incorporation of G and GO increased surface properties(reduced modulus and wettability),material crystallinity,crystallization temperature,and degradation rate.However,the variations in compressive modulus,strength,surface hardness,and cell metabolic activity strongly depended on the type of reinforcement.Finally,a series of phenomenological models were developed based on experimental results to describe the variations of scaffold’s weight,fiber diameter,porosity,and mechanical properties as functions of degradation time and carbon nanomaterial concentrations.The results presented in this paper enable the design of three-dimensional(3D)bone scaffolds with tuned properties by adjusting the type and concentration of different functional fillers.
基金supported by the National Natural Science Foundation of China(Grant no:12272253)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(Grant no:2021SX-AT008,2021SX-AT009).
文摘Bone is a complex but orderly mineralized tissue with hydroxyapatite(HA)as the inorganic phase and collagen as the organic phase.Inspired by natural bone tissues,HA-mineralized hydrogels have been widely designed and used in bone tissue engineering.HA is majorly utilized for the treatment of bone defects because of its excellent osteoconduction and bone inductivity.Hydrogel is a three-dimensional hydrophilic network structure with similar properties to the extracellular matrix(ECM).The combination of HA and hydrogels produces a new hybrid material that could effectively promote osteointegration and accelerate the healing of bone defects.In this review,the structure and growth of bone and the common strategies used to prepare HA were briefly introduced.Importantly,we discussed the fabrication of HA mineralized hydrogels from simple blending to in situ mineralization.We hope this review can provide a reference for the development of bone repair hydrogels.
文摘Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have been recognized for their biocompatibility and biodegradability.However,their susceptibility to rapid corrosion and degradation has garnered notable research interest in bone tissue engineering(BTE),particularly in the development of Mg-incorporated biocomposite scaffolds.These scaffolds gradually release Mg2+,which enhances immunomodulation,osteogenesis,and angiogenesis,thus facilitating effective bone regeneration.This review presents myriad fabrication techniques used to create Mg-incorporated biocomposite scaffolds,including electrospinning,three-dimensional printing,and sol-gel synthesis.Despite these advancements,the application of Mg-incorporated biocomposite scaffolds faces challenges such as controlling the degradation rate of Mg and ensuring mechanical stability.These limitations highlight the necessity for ongoing research aimed at refining fabrication techniques to better regulate the physicochemical and osteogenic properties of scaffolds.This review provides insights into the potential of Mg-incorporated biocomposite scaffolds for BTE and the challenges that need to be addressed for their successful translation into clinical applications.
文摘Identifying an effective way to promote bone regeneration for patients who suffer from bone defects is urgently demanded.In recent years,mesenchymal stem cells(MSCs)have drawed wide attention in bone regeneration.Besides,several studies have indicated the secretions of MSCs,especially exosomes,play a vital role in bone regeneration process.Exosomes can transfer“cargos”of proteins,RNA,DNA,lipids,to regulate fate of recipient cells by affecting their proliferation,differentiation,migration and gene expression.In this paper,the application of MSCs-derived exosomes in bone tissue engineering is reviewed,and the potential therapeutic role of exosome microRNA in bone regeneration is emphasized.
文摘A new biomimetic bone tissue engineering scaffold material, nano-HAI PLGA-( PEG-Asp )n composite, was synthesized by a biologically inspired self-assembling approach. A novel biodegradable PLGA- ( PEG-Asp )n copolymer with pendant amine functional groups and enhanced hydrophilicity woo synthesized by bulk ring-opening copolymerization by DL-lactide( DLLA) and glycolide( GA ) with Aspartic acid ( Asp )-Polyethylene glycol(PEG) alt-prepolymer. A Three-dimensional, porous scaffold of the PLGA-( PEG- Asp)n copolymer was fabricated by a solvent casting , particulate leaching process. The scaffold woo then incubated in modified simulated body fluid (naSBF). Growth of HA nanocrystals on the inner pore surfaces of the porous scaffold is confirmed by calcium ion binding analyses, SEM , mass increooe meoourements and quantification of phosphate content within scaffolds. SEM analysis demonstrated the nucleation and growth of a continuous bonelike, low crystalline carbonated HA nanocrystals on the inner pore surfaces of the PLGA- ( PEG-Asp )n scaffolds. The amount of calcium binding, total mass and the mass of phosphate on experimental PLGA- ( PEG-Asp ) n scaffolds at different incubation times in mSBF was significantly greater than that of control PLGA scaffolds. This nano-HA/ PLGA-( PEG- Asp )n composite stunts some features of natural bone both in main composition and hierarchical microstrueture. The Asp- PEG alt-prepolymer modified PleA copolymer provide a controllable high surface density and distribution of anionic functional groups which would enhance nucleation and growth of bonelike mineral following exposure to mSBF. This biomimetic treatment provides a simple method for surface functionalization and sabsequent mineral nucleation and self-oosembling on bodegradable polymer scaffolds for tissue engineering.
基金Supported by The Regione Toscana-POR CRO FSE 2007-2013 and I.F.B.STRODER s.r.l
文摘Bone tissue engineering represents one of the most challenging emergent fields for scientists and clinicians.Current failures of autografts and allografts in many pathological conditions have prompted researchers to find new biomaterials able to promote bone repair or regeneration with specific characteristics of biocompatibility,biodegradability and osteoinductivity.Recent advancements for tissue regeneration in bone defects have occurred by following the diamond concept and combining the use of growth factors and mesenchymal stem cells(MSCs).In particular,a more abundant and easily accessible source of MSCs was recently discovered in adipose tissue.These adipose stem cells(ASCs)can be obtained in large quantities with little donor site morbidity or patient discomfort,in contrast to the invasive and painful isolation of bone marrow MSCs.The osteogenic potential of ASCs on scaffolds has been examined in cell cultures and animal models,with only a few cases reporting the use of ASCs for successful reconstruction or accelerated healing of defects of the skull and jaw in patients.Although these reports extend our limited knowledge concerning the use of ASCs for osseous tissue repair and regeneration,the lack of standardization in applied techniques makes the comparison between studies difficult.Additional clinical trials are needed to assess ASC therapy and address potential ethical and safety concerns,which must be resolved to permit application in regenerative medicine.
基金supported by grants from Shenzhen Key Medical Subject(No.SZXK023)Shenzhen“SanMing”Project of Medicine(No.SZSM201612092)+3 种基金Shenzhen Research and Development Projects(No.JCYJ20170307111755218)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515011290)National Key Research and Development Program of China(No.2016YFC1102103)China Postdoctoral Science Foundation(No.2020M672756)
文摘Interconnectivity is the key characteristic of bone tissue engineering scaffold modulating cell migration,blood vessels invasion and transport of nutrient and waste.However,efforts and understanding of the interconnectivity of porous Mg is limited due to the diverse architectures of pore struts and pore size distribution of Mg scaffold systems.In this work,biomimetic hierarchical porous Mg scaffolds with tailored interconnectivity as well as pore size distribution were prepared by template replication of infiltration casting.Mg scaffold with better interconnectivity showed lower mechanical strength.Enlarging interconnected pores would enhance the interconnectivity of the whole scaffold and reduce the change of ion concentration,pH value and osmolality of the degradation microenvironment due to the lower specific surface area.Nevertheless,the degradation rates of five tested Mg scaffolds were no different because of the same geometry of strut unit.Direct cell culture and evaluation of cell density at both sides of four typical Mg scaffolds indicated that cell migration through hierarchical porous Mg scaffolds could be enhanced by not only bigger interconnected pore size but also larger main pore size.In summary,design of interconnectivity in terms of pore size distribution could regulate mechanical strength,microenvironment in cell culture condition and cell migration potential,and beyond that it shows great potential for personalized therapy which could facilitate the regeneration process.
文摘BACKGROUND In the medical and dental fields,there is a need for studies of new therapeutic approaches for the treatment of bone defects that cause extensive bone loss.Melatonin may be an important endogenous biological factor for bone remodeling,and growth factors may enhance the repair process.AIM To evaluate the gene expression of cytokines(IL-1β,IL-6,IL-10 and TNF-α),markers of osteoclastogenesis(RANK,RANKL and OPG)and MMPs(MMP-1,MMP-2,MMP-8 and MMP-13)from the treatment of melatonin associated with an osteogenic membrane and rhBMP-2 on the recovery of a bone injury.METHODS Sixty-four rats were used and divided into 9 experimental groups and were formed according to the treatment carried out in the region of the bone lesion,which varied between the combination of 1,10 and 100μmol/L of melatonin.Gene Expression analysis was performed using real time-PCR by reading the concentration of total RNA and reverse transcription.RESULTS There were differences between groups when compared with clot or scaffold control,and improvement with a higher concentration of melatonin or rhBMP-2.The combination melatonin(1μg)with 5μg of rhBMP-2,using the guided bone regeneration technique,demonstrated some effects,albeit mild,on bone repair of critical bone defects.CONCLUSION This indicates that the approach for administering these substances needs to be reassessed,with the goal of ensuring their direct application to the affected area.Therefore,future research must be carried out,seeking to produce materials with these ideal characteristics.
基金CAMS Innovation Fund for Medical Sciences,No.2022-I2M-C&T-B-034.
文摘Peripheral nerve injury(PNI)is a common neurological disorder and complete functional recovery is difficult to achieve.In recent years,bone marrow mesenchymal stem cells(BMSCs)have emerged as ideal seed cells for PNI treatment due to their strong differentiation potential and autologous trans-plantation ability.This review aims to summarize the molecular mechanisms by which BMSCs mediate nerve repair in PNI.The key mechanisms discussed include the differentiation of BMSCs into multiple types of nerve cells to promote repair of nerve injury.BMSCs also create a microenvironment suitable for neuronal survival and regeneration through the secretion of neurotrophic factors,extracellular matrix molecules,and adhesion molecules.Additionally,BMSCs release pro-angiogenic factors to promote the formation of new blood vessels.They modulate cytokine expression and regulate macrophage polarization,leading to immunomodulation.Furthermore,BMSCs synthesize and release proteins related to myelin sheath formation and axonal regeneration,thereby promoting neuronal repair and regeneration.Moreover,this review explores methods of applying BMSCs in PNI treatment,including direct cell trans-plantation into the injured neural tissue,implantation of BMSCs into nerve conduits providing support,and the application of genetically modified BMSCs,among others.These findings confirm the potential of BMSCs in treating PNI.However,with the development of this field,it is crucial to address issues related to BMSC therapy,including establishing standards for extracting,identifying,and cultivating BMSCs,as well as selecting application methods for BMSCs in PNI such as direct transplantation,tissue engineering,and genetic engineering.Addressing these issues will help translate current preclinical research results into clinical practice,providing new and effective treatment strategies for patients with PNI.
文摘AIM: To improve osteogenic differentiation and attachment of cells.METHODS: An electronic search was conducted inPub Med from January 2004 to December 2013. Studies which performed smart modifications on conventional bone scaffold materials were included. Scaffolds with controlled release or encapsulation of bioactive molecules were not included. Experiments which did not investigate response of cells toward the scaffold(cell attachment, proliferation or osteoblastic differentiation) were excluded. RESULTS: Among 1458 studies, 38 met the inclusion and exclusion criteria. The main scaffold varied extensively among the included studies. Smart modifications included addition of growth factors(group Ⅰ-11 studies), extracellular matrix-like molecules(group Ⅱ-13 studies) and nanoparticles(nano-HA)(group Ⅲ-17 studies). In all groups, surface coating was the most commonly applied approach for smart modification of scaffolds. In group I, bone morphogenetic proteins were mainly used as growth factor stabilized on polycaprolactone(PCL). In group Ⅱ, collagen 1 in combination with PCL, hydroxyapatite(HA) and tricalcium phosphate were the most frequent scaffolds used. In the third group, nano-HA with PCL and chitosan were used the most. As variable methods were used, a thorough and comprehensible compare between the results and approaches was unattainable.CONCLUSION: Regarding the variability in methodology of these in vitro studies it was demonstrated that smart modification of scaffolds can improve tissue properties.
基金supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases,and National Institute of Dental and Craniofacial Research under Award Numbers AR061052,AR066101 and DE023105 to S.Y
文摘Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors(GFs), it makes stem cells the ideal agents for bone regeneration.Furthermore, platelet-rich plasma(PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.
基金Supported by National Natural Science Foundation of China(Grant Nos.51675312,51375273)
文摘A novel method was proposed to design the structure of a bone tissue engineering scafold based on triply periodic minimal surface.In this method,reverse engineering software was used to reconstruct the surface from point cloud data.This method overcomes the limitations of commercially available software packages that prevent them from generating models with complex surfaces used for bone tissue engineering scafolds.Additionally,the fluid feld of the scafolds was simulated through a numerical method based on fnite volume and the cell proliferation performance was evaluated via an in vitro experiment.The cell proliferation and the mass flow evaluated in a bioreactor further verifed the flow feld simulated using computational fluid dynamics.The result of this study illustrates that the pressure value drops rapidly from 0.103 Pa to 0.011 Pa in the y-axis direction and the mass flow is unevenly distributed in the outlets.The mass flow in the side outlets is observed to be approximately 24.3 times higher thanthe bottom.Importantly,although the mean value of wall shear stress is signifcantly more than 0.05 Pa,there is stil a large area with a suitable shear stress below 0.05 Pa where most cells can proliferate well.The result shows that th inlet velocity 0.0075 m/s is suitable for cell proliferation in the scafold.This study provides an insight into the design analysis,and in vitro experiment of a bone tissue engineering scafold.
基金Supported by grants from the National Natural Science Foundation Key Project of China(10832012)the National Natural Science Foundation of China(31370942 and 11072266)
文摘Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods Cancellous bone were extracted from rabbit femoral head and cut into I-ram-thick and 8-ram-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 με respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase (AKP) and tartrate-resistant acid phosphatase (TRAP) were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. Results After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 με were significantly lower than those in the unstressed bone tissues (all P〈0.05). DNA ladders were seen in the bone tissue under 3000 and 4000με mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 με (all P〈0.05). Conclusions The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteobiasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 με.
基金National Natural Science Foundation of China,No.81271122 and No.81371122Shanghai Leading Academic Discipline Project,No.S30206
文摘In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.
文摘Fibrous hydroxyapatite ( HA ) wns grown upwards from the crosslinked unsaturated polyphosphoester( UPPE ) which was used us an injectable bone tissue engineering scaffolds. Composition of fibrous HA was determined by FT- IR, XRD and EDX, which suggested that the fibrous HA was calcium deficient carbonated apatitie with low crystallinity. SEM micrographs indicated that the fibrous HA had a hollow tubing structure and tube wall wus a flakelike assembly. The fibre with poor mechanical property arm with a growth rate about 0. 5 mm/min reached several centimeters in length after 2 hours. The growth was at the tip of the fibre suggested that the procedure of forming fibrous HA was as follows : Co^2+ ions were firstly incorporated into the crosslinked UPPE by dipping in Ca^2+ solution, then supplied through micropores of the material reacted with PO4^3- ions to form α small tuhe , the osmotic pressure or capillary force lead the Ca^2+ continuously gushed oat into the PO4^3- solution, thus fibrous HA was obtained.
基金Funded by the Postdoctor Science Fund of China (No. 20070410715) Shanghai Excellent Youth Special Fund (No. 17014)
文摘A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macro channels' shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200-400 μm. The porosity and connectivity of micro pores became higher with the increase of porogen ratio, while the mechanical properties weakened. The average porosity and compressive strength offl-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 MPa, respectively. The cells' adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds.
基金"111 Project"Biomedical Textile Materials Science and Technology,China(No.B07024)National Natural Science Foundations of China(No.31070871,No.31271035)+2 种基金National Medical Research Council,China(No.NMRC/1151/2008)Technologies Bureau of Jiaxing City,China(No.MTC2012-006,No.2011A Y1026)Science and Technology Agency of Zhejiang Province,China(No.2012R10012-09)
文摘Composite nanofibrous mats consisting of poly( L-lactideco-ε-caprolactone)( PLCL) and collagen type I( COL) were fabricated by electrospinning,and ten times simulated body fluid(10SBF) were employed to mineralize nanofibrous mats. Ballshaped hydroxyapatite( HA) was deposited on the surface of nanofibrous mats in 1. 5 h at room temperature. Human fetal osteoblasts( hFob) were seeded to investigate their proliferation and differentiation on mineralized composite nanofibrous mats. The results showed that hFob grew well on mineralized composite nanofibrous mats and alkaline phosphatase( ALP) activity of hFob on mineralized composite nanofibrous mats at 14 d was much higher than that on untreated nanofibrous mats. Moreover,the expression of osteocalcin of cells on mineralized composite nanofibrous mats was also much higher than those on untreated nanofibrous mats at 7 d and 14 d. This mineralized composite nanofibrous mats may have a great potential for bone tissue engineering.
文摘To study the osteogenic ability of tissue-engineered bone constructed by compounding zinc-sintered bovine cancellous bone with rabbit marrow stromal cells (MSCs) in vivo,the zinc-sintered bovine cancellous bone of beta-tricalcium phosphate (TCP) type was prepared by sintering the fresh calf cancellous bone twice and then loading it with zinc-ion.The rabbit MSCs were cultured,induced and seeded onto the zinc-sintered bovine cancellous bones.The tissue-engineered bones were then implanted into the rabbits' back muscles.The newly formed bone tissues were observed by histological methods and the areas of new osseous tissues were measured at the end of the 4th and 8th week.The zinc-sintered bovine cancellous bones alone were implanted on the other side as control.The osteogenic activity of MSCs was identified by alkaline phosphatase (ALP) staining and calcification nod chinalizarin staining.At the end of 4th week,a small amount of new bone tissues was observed.At the end of 8th week,there were many newly formed bone mature tissues.Moreover,the area of the latter was significantly larger than that of the former(P<0.01),while in the control group there was no new bone formation.The tissue-engineered bone,which was constructed by combining zinc-sintered bovine cancellous bone with MSCs,has satisfactory osteogenic capabilities in vivo.
基金the Fundamental Research Funds for the Central Universities,China(No.14D110519)Pujiang Talent Program Funded by the Science and Technology Commission of Shanghai Municipality,China(No.10PJ1400200)National Natural Science Foundation of China(No.51073032)
文摘Biodegradable shape memory polymers( SMPs) are a class of intelligent materials with great potential for imparting biomaterial scaffolds multifunctionality in the field of tissue engineering and regenerative medicine.In this study,the biodegradable SMP poly( D,L-lactide-co-trimethylene carbonate)( PLMC) incorporated with the dexamethasone( Dex),which was a kind of synthetic bone-formation inducing factor,was fabricated into nanofibers via electrospinning.The morphology,constituent,thermal and mechanical properties of the produced Dex / PLMC composite nanofibers were characterized by scanning electron microscopy( SEM), Fourier transform infrared spectroscopy( FTIR), differential scanning calorimetry( DSC),and tensile testing,respectively.Then,ultrasound was employed as a remote stimulus to regulate the Dex releasing behavior from the composite nanofibers.It was found that the generated Dex /PLMC composite nanofibers had a uniform and smooth morphology with a diameter of ca.564 nm.Mechanical testing results showed that incorporation of the Dex gave rise to improved mechanical performance with the tensile strength,Young's modulus and strainat-break increased by 18.2%,20.0% and 64.4%,respectively.DSC data revealed that the glass transition temperature( Tg) of the composite nanofibers, i.e., the thermal transition temperature( Ttrans) for activating shape memory effect, was 39.7 ℃.Moreover, the release kinetics of the encapsulated Dex in the nanofibers could be manipulated by varying the acoustic power and insonation duration.These results suggested that the newly developed Dex / PLMC nanofibers could be a promising drug delivery system for applications in bone tissue engineering( BTE).
文摘Tissue engineering’s main goal is to regenerate or replace tissues or organs that have been destroyed by disease,injury,or congenital disabilities.Tissue engineering now uses artificial supporting structures called scaffolds to restore damaged tissues and organs.These are utilized to attach the right cells and then grow them.Rapid prototyping appears to be the most promising technology due to its high level of precision and control.Bone tissue replacement“scaffolding”is a common theme discussed in this article.The fused deposition technique was used to construct our scaffold,and a polymer called polylactic acids and soybean oil resin were used to construct our samples.The samples were then divided into two groups;the first group was left without immersion in the simulated body fluid and served as a control for comparison.The second group was immersed in the simulated body fluid.The results of the Field Emission Scanning Electron Microscope(FESEM),Energy Dispersive X-ray Spectroscopy(EDX)and X-ray diffraction(XRD)were utilized to interpret the surface attachment to ions,elements,and compounds,giving us a new perspective on scaffold architecture.In this study,an innovative method has been used to print therapeutic scaffold that combines fused deposition three-dimensional printing with ultraviolet curing to create a high-quality biodegradable polymeric scaffold.Finally,the results demonstrate that adding soybean oil resin to the PLA increased ion attachment to the surface while also attracting tricalcium phosphate formation on the surface of the scaffold,which is highly promising in bone tissue replacement.In conclusion,the soybean oil resin,which is new in the field of bone tissue engineering,shows magnificent characteristics and is a good replacement biopolymer that replaces many ceramic and polymeric materials used in this field that have poor morphological characteristics.