EFL preservice teachers ’ research efficacy, as perceived competence to perform tasks in research, is crucial to their research engagement. This autobiographical narrative inquiry investigates the contribution of sca...EFL preservice teachers ’ research efficacy, as perceived competence to perform tasks in research, is crucial to their research engagement. This autobiographical narrative inquiry investigates the contribution of scaffolded research practice to a female EFL preservice teacher ’s research efficacy.The data were collected through conversations, notes, journals, and portfolios. The findings suggest that teacher research efficacy was pliable through scaffolded research practice. It emerged gradually over time, in different places with social and personal interaction. The factors contributing to the emerging research efficacy were: teacher educators ’ support, peers ’ support,and research participation. The study sheds light on teacher educators and EFL preservice teachers,with the intention of establishing an inquiry-based pedagogy for M.Ed. programs.展开更多
Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of capacitors.Titanium dioxide(TiO_(2)),is a promising anode material.Its performance is...Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of capacitors.Titanium dioxide(TiO_(2)),is a promising anode material.Its performance is however seriously hindered by its low electrical conductivity and the sluggish diffusion of sodium ions(Na^(+))in the TiO_(2)matrix.Herein,this work combines porous TiO_(2)nanocubes with carbon nanotubes(CNTs)to enhance the electrical conductivity and accelerate Na^(+)diffusivity for Na-ion batteries(NIBs).In this composite,an interwoven scaffolded TiO_(2)/CNTs framework is formed to provide abundant channels and shorter diffusion pathways for electrons and ions.The in-situ X-ray diffraction and cyclic voltammetry confirm the low strain and superior transport kinetics in Na^(+)intercalation/extraction processes.In addition,the chemically bonded TiO_(2)/CNTs hybrid provides a more feasible channel for Na^(+)insertion/extraction with a much lower energy barrier.Consequently,the TiO_(2)/CNTs composite exhibits excellent electrochemical performance with a capacity of 223.4 m Ah g^(-1)at 1 C and a capacity of 142.8 m Ah g^(-1)at 10 C(3.35 A g^(-1)).The work here reveals that the combination of active materials with CNTs can largely improve the utilization efficiency and enhance their sodium storage.展开更多
Background:The development of materials for cardiovascular surgery that would improve the effectiveness of surgical interventions remains an important task.Surgical intervention during the implantation of vascular pro...Background:The development of materials for cardiovascular surgery that would improve the effectiveness of surgical interventions remains an important task.Surgical intervention during the implantation of vascular prostheses and stents,and the body’s reaction to artificial materials,could lead to chronic inflammation,a local increase in the concentration of proinflammatory factors,and stimulation of unwanted tissue growth.The introduction of nonsteroidal anti-inflammatory drugs into implantable devices could be used to obtain vascular implants that do not induce inflammation and do not induce neointimal tissue outgrowth.Methods:The scaffolds were made by electrospinning from mixtures of polyurethane(PU)with diclofenac(DF).The kinetics of DF release from the scaffolds composed of 3%PU/10%HSA/3%DMSO/DF and 3%PU/DF were studied.The biocompatibility and anti-inflammatory effects of the obtained scaffolds on human gingival fibroblasts and umbilical vein endothelial cells were studied.Results:Both types of scaffolds are characterized by fast DF release.The viability of cells cultured on scaffolds is 2 times worse than that of cells cultured on plastic.The level of the proinflammatory cytokine IL-6 in the culture medium of cells cultured on DF-containing scaffolds was lower than that of cells cultured on scaffolds without DF.Conclusion:The introduction of DF into scaffolds minimizes the inflammation caused by cell reactions to an artificial material.展开更多
Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaff...Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.展开更多
From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganu...From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganumium C(3)were ionic alkaloid salts and peganumium B was a hexacycliccondensed alkaloid.The biosynthetic pathways of the three compounds above were also speculated.A preliminary cytotoxicity assay revealed that peganumium B had strong in vitro antiproliferative ability against a variety of cancer cells.The analysis of^(1)H nuclear magnetic resonance(NMR)metabolomics suggested that the antiproliferative mechanism of peganumium B could be associated with the biosynthesis of phenylalanine,tyrosine and tryptophan,the metabolism of glycine,serine,and threonine,the metabolism of taurine and hypotaurine,and the metabolism of nicotinate and nicotinamide.In addition,peganumium B could reduce the mitochondrial content of body-wall muscle cells of a Caenorhabditis elegans(C.elegans)strain in vivo.展开更多
Porous designs effectively reduce stress shielding in metallic orthopedic implants.However,current porous structures often fail to adequately meet the needs of patients with osteoporosis and low-modulus body regions.T...Porous designs effectively reduce stress shielding in metallic orthopedic implants.However,current porous structures often fail to adequately meet the needs of patients with osteoporosis and low-modulus body regions.This study proposes a sinusoidal-based lattice structure for an ultralow and widely tunable modulus design,aiming to match diverse bone tissue requirements and enhance biomechanical compatibility.Parametric modeling and finite element analysis were used to evaluate the performance of this structure.Results show that,within the design range suitable for bone growth,the elastic modulus of this lattice structure is tunable over a wide range,from 0.09 to 32.67 GPa,outperforming existing porous structures.The lowest value closely matched the minimum mechanical properties of human cancellous bone among porous structures.Moreover,the structure exhibited distinct anisotropic characteristics,allowing for directional design based on mechanical requirements.The structure’s permeability ranged from 1.19×10^(-8) m^(2) to 2.3×10^(-7) m^(2),making it highly compatible with human cancellous bone and meeting the requirements of orthopedic implants.Samples with porosities ranging from 46% to 87% were successfully fabricated using powder bed fusion additive manufacturing,validating the simulation predictions.This tunable low-modulus lattice structure provides a novel approach for developing personalized orthopedic implants,particularly for patients with specialized needs such as osteoporosis,and can potentially enhance biomechanical compatibility and long-term stability.展开更多
Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently.Spinal cord injury is associated with a complex molecular and cellular microenvironment.This co...Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently.Spinal cord injury is associated with a complex molecular and cellular microenvironment.This complexity has prompted researchers to elucidate the underlying pathophysiological mechanisms and changes and to identify effective treatment strategies.Traditional approaches for spinal cord injury repair include surgery,oral or intravenous medications,and administration of neurotrophic factors;however,the efficacy of these approaches remains inconclusive,and serious adverse reactions continue to be a concern.With advancements in tissue engineering and regenerative medicine,emerging strategies for spinal cord injury repair now involve nanoparticle-based nanodelivery systems,scaffolds,and functional recovery techniques that incorporate biomaterials,bioengineering,stem cell,and growth factors as well as three-dimensional bioprinting.Ideal biomaterial scaffolds should not only provide structural support for neuron migration,adhesion,proliferation,and differentiation but also mimic the mechanical properties of natural spinal cord tissue.Additionally,these scaffolds should facilitate axon growth and neurogenesis by offering adjustable topography and a range of physical and biochemical cues.The three-dimensionally interconnected porous structure and appropriate physicochemical properties enabled by three-dimensional biomimetic printing technology can maximize the potential of biomaterials used for treating spinal cord injury.Therefore,correct selection and application of scaffolds,coupled with successful clinical translation,represent promising clinical objectives to enhance the treatment efficacy for and prognosis of spinal cord injury.This review elucidates the key mechanisms underlying the occurrence of spinal cord injury and regeneration post-injury,including neuroinflammation,oxidative stress,axon regeneration,and angiogenesis.This review also briefly discusses the critical role of nanodelivery systems used for repair and regeneration of injured spinal cord,highlighting the influence of nanoparticles and the factors that affect delivery efficiency.Finally,this review highlights tissue engineering strategies and the application of biomaterial scaffolds for the treatment of spinal cord injury.It discusses various types of scaffolds,their integrations with stem cells or growth factors,and approaches for optimization of scaffold design.展开更多
Numerous c-mesenchymal-epithelial transition(c-MET)inhibitors have been reported as potential anticancer agents.However,most fail to enter clinical trials owing to poor efficacy or drug resistance.To date,the scaffold...Numerous c-mesenchymal-epithelial transition(c-MET)inhibitors have been reported as potential anticancer agents.However,most fail to enter clinical trials owing to poor efficacy or drug resistance.To date,the scaffold-based chemical space of small-molecule c-MET inhibitors has not been analyzed.In this study,we constructed the largest c-MET dataset,which included 2,278 molecules with different struc-tures,by inhibiting the half maximal inhibitory concentration(IC_(50))of kinase activity.No significant differences in drug-like properties were observed between active molecules(1,228)and inactive mol-ecules(1,050),including chemical space coverage,physicochemical properties,and absorption,distri-bution,metabolism,excretion,and toxicity(ADMET)profiles.The higher chemical diversity of the active molecules was downscaled using t-distributed stochastic neighbor embedding(t-SNE)high-dimensional data.Further clustering and chemical space networks(CSNs)analyses revealed commonly used scaffolds for c-MET inhibitors,such as M5,M7,and M8.Activity cliffs and structural alerts were used to reveal“dead ends”and“safe bets”for c-MET,as well as dominant structural fragments consisting of pyr-idazinones,triazoles,and pyrazines.Finally,the decision tree model precisely indicated the key structural features required to constitute active c-MET inhibitor molecules,including at least three aromatic het-erocycles,five aromatic nitrogen atoms,and eight nitrogeneoxygen atoms.Overall,our analyses revealed potential structure-activity relationship(SAR)patterns for c-MET inhibitors,which can inform the screening of new compounds and guide future optimization efforts.展开更多
Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation...Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation.In this study,a composite bioink composed of methacrylated gelatin(GelMA)and chitosan oligosaccharide(COS)was proposed for printing a dermal scaffold using digital light processing(DLP)technology.The GelMA/COS bioink exhibited suitable porosity,swelling,degradation rate,and mechanical properties.The inclusion of COS demonstrated antibacterial effects against both Gram positive and Gram-negative bacteria,while simultaneously fostering the proliferation of human dermal fibroblasts(HDFs).Additionally,the application of COS could effectively reduce the expression levels of fibrosis-related genes,such as collagen I,collagen III,and fibronectin I.The three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability,facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix proteins.Furthermore,the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure,reduce inflammation,and improve wound healing.Overall,the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.展开更多
Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomime...Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomimetic scaffold aimed at facilitating rapid and scarless wound healing.This highly in-tegrated 3D-printed dermal scaffold comprised modified recombinant human type III collagen(rhCOLIII-MA),gelatin methacrylate(GelMA),and liposomes encapsulating SB431542 to target TGF-β1(Lip@SB).The rhCOLIII-MA/GelMA(CG)scaffold retained inherent biomaterial characteristics,exhibited tailored physicochemical properties,and demonstrated favorable biocompatibility.Moreover,the Lip@SB-loaded CG scaffold(CGL)effectively promoted in vitro wound healing,while enabling controlled release of SB431542 to inhibit pathological collagen deposition.In a full-thickness skin defect rat model,the CGL dermal scaffold combined with split-thickness skin graft(STSG)minimized scar contraction,stimulated functional neovascularization,and enhanced graft aesthetics comparable to normal skin.Remarkably,the performance of the CGL scaffold surpassed that of commercially available anti-scarring alternatives.This innovative strategy presents a straightforward approach toward scarless skin regeneration and holds promise in alleviating the prolonged,painful postoperative rehabilitation.展开更多
The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.T...The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.展开更多
Current modifications of Ti-based materials with porous scaffolds for achieving biological fixation often decrease corrosion fatigue strength(σ_(cf))of the resultant implants,thereby shortening their service lifes-pa...Current modifications of Ti-based materials with porous scaffolds for achieving biological fixation often decrease corrosion fatigue strength(σ_(cf))of the resultant implants,thereby shortening their service lifes-pan.To resolve this issue,in the present,a step-wise graded porous Ti-6Al-7Nb scaffold was additively manufactured on optimally surface mechanical attrition treated(SMATed)Ti-6Al-7Nb(specifically de-noted as S-Ti6Al7Nb)using laser powder bed fusion(PBF)technology.The microstructure,bond strength,residual stress distribution,and corrosion fatigue behavior of porous scaffolds modified S-Ti6Al7Nb were investigated and compared with those of mechanically polished Ti-6Al-7Nb(P-Ti6Al7Nb),S-Ti6Al7Nb,and porous scaffolds modified P-Ti6Al7Nb.Results showed that corrosion fatigue of porous scaffolds modi-fied Ti-6Al-7Nb was propagation controlled.Moreover,the crack propagation behavior in the PBF scaf-fold’s fusion zone(FZ)and heat-affected zone(HAZ),exhibiting insensitivity to the microstructural con-figurations characterized by columnar prior-βgrain(PBG)boundaries and acicularα''martensites,cou-pled with the PBF-induced residual tensile stresses in these regions,resulted in a considerable decrease inσ_(cf) for porous scaffolds modified P-Ti6Al7Nb compared to P-Ti6Al7Nb.In contrast,step-wise graded porous scaffold-modified S-Ti6Al7Nb demonstrated an improvedσ_(cf) which was even higher than that of P-Ti6Al7Nb.Such an advancement in corrosion fatigue strength is primarily attributed to the presence of residual compressive stresses within the underlying S-Ti6Al7Nb substrate,extending beyond FZ and HAZ.These stresses increased the crack propagation threshold,leading to crack deflection/branching and increased crack-path tortuosity,thereby synergistically markedly enhancing the crack propagation resis-tance of porous scaffolds modified S-Ti6Al7Nb.展开更多
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
Introduction It is necessary for an ideal bioceramic scaffold to have a suitable structure.The structure can affect the mechanical properties of the scaffold(i.e.,elastic modulus and compressive strength)and the biolo...Introduction It is necessary for an ideal bioceramic scaffold to have a suitable structure.The structure can affect the mechanical properties of the scaffold(i.e.,elastic modulus and compressive strength)and the biological properties of the scaffold(i.e.,degradability and cell growth rate).Lattice structure is a kind of periodic porous structure,which has some advantages of light weight and high strength,and is widely used in the preparation of bioceramic scaffolders.For the structure of the scaffold,high porosity and large pore size are important for bone growth,bone integration and promoting good mechanical interlocking between neighboring bones and the scaffold.However,scaffolds with a high porosity often lack mechanical strength.In addition,different parts of the bone have different structural requirements.In this paper,scaffolds with a non-uniform structure or a hierarchical structure were designed,with loose and porous exterior to facilitate cell adhesion,osteogenic differentiation and vascularization as well as relatively dense interior to provide sufficient mechanical support for bone repair.Methods In this work,composite ceramics scaffolds with 10%akermanite content were prepared by DLP technology.The scaffold had a high porosity outside to promote the growth of bone tissue,and a low porosity inside to withstand external forces.The compressive strength,fracture form,in-vitro degradation performance and bioactivity of graded bioceramic scaffolds were investigated.The models of scaffolds were imported into the DLP printer with a 405 nm light.The samples were printed with the intensity of 8 mJ/cm^(2)and a layer thickness of 50μm.Finally,the ceramic samples were sintered at 1100℃.The degradability of the hierarchical gyroid bioceramic scaffolds was evaluated through immersion in Tris-HCl solution and SBF solution at a ratio of 200 mL/g.The bioactivity of bioceramic was obtained via immersing them in SBF solution for two weeks.The concentrations of calcium,phosphate,silicon,and magnesium ions in the soaking solution were determined by an inductively coupled plasma optical emission spectrometer.Results and discussion In this work,a hierarchical Gyroid structure HA-AK10 scaffold(sintered at 1100℃)with a radial internal porosity of 50%and an external porosity of 70%is prepared,and the influence of structural form on the compressive strength and degradation performance of the scaffold is investigated.The biological activity of the bioceramics in vitro is also verified.The mechanical simulation results show that the stress distribution corresponds to the porosity distribution of the structure,and the low porosity is larger and the overall stress concentration phenomenon does not appear.After soaking in SBF solution,Si—OH is firstly formed on the surface of bioceramics,and then silicon gel layer is produced due to the presence of calcium and silicon ions.The silicon gel layer is dissociated into negatively charged groups under alkaline environment secondary adsorption of calcium ions and phosphate ions,forming amorphous calcium phosphate,and finally amorphous calcium phosphate crystals and adsorption of carbonate ions,forming carbonate hydroxyapatite.This indicates that the composite bioceramics have a good biological activity in-vitro and can provide a good environment for the growth of bone cells.A hierarchical Gyroid ceramic scaffold with a bone geometry is prepared via applying the hierarchical structure to the bone contour scaffold.The maximum load capacity of the hierarchical Gyroid ceramic scaffold is 8 times that of the uniform structure.Conclusions The hierarchical structure scaffold designed had good overall compressive performance,good degradation performance,and still maintained a good mechanical stability during degradation.In addition,in-vitro biological experimental results showed that the surface graded composite scaffold could have a good in-vitro biological activity and provide a good environment for bone cells.Compared to the heterosexual structure,the graded scaffold had greater mechanical properties.展开更多
Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser m...Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser melting.Their forming quality,compression mechanical properties,and degradation behavior were investigated.Results indicate that the fabricated scaffolds exhibit good dimensional accuracy,and the surface chemical polishing treatment significantly improves the forming quality and reduces porosity error in porous scaffolds.Compared to the ones with rod structures(bcc,RD),the scaffolds with surface structures(G,P)have less powder particle adhesion.The G porous scaffold exhibits the best forming quality for the same design porosity.The predominant failure mode of scaffolds during compression is a 45°shear fracture.At a porosity of 75%,the compression property of all scaffolds meets the compressive property requirements of cancellous bone,while bcc and G structures show relatively better compression property.After immersion in Hank's solution for 168 h,the B-2-75% pore structure scaffold exhibits severe localized corrosion,with fractures in partial pillar connections.In contrast,the G-3-75% pore structure scaffold mainly undergoes uniform corrosion,maintaining structural integrity,and its corrosion rate and loss of compressive properties are less than those of the B-2-75%structure.After comparison,the G-pore structure scaffold is preferred.展开更多
Pyridazine has garnered increasing attention as a privileged scaffold and bioisosterism in drug discovery due to its unique structural characteristics.It can serve as a hydrogen bond acceptor when interacting with rec...Pyridazine has garnered increasing attention as a privileged scaffold and bioisosterism in drug discovery due to its unique structural characteristics.It can serve as a hydrogen bond acceptor when interacting with receptors due to its two adjacent nitrogen atoms.Upon conversion to pyridazinone,it exhibits the ability to act as both a hydrogen bond acceptor and donor,showcasing its versatility.This inherent flexibility has prompted extensive research exploring its bioactivity in pesticides and pharmaceuticals.In order to promote the development of pyridazine-based pesticides,this review provides a comprehensive summary of advancements for pyridazine-based pesticides on herbicidal(36.9%),insecticidal(26.2%),antifungal and antibacterial(24.6%),plant growth regulatory(10.8%),and antiviral activities(1.5%)from2000 to 2024.It serves as an invaluable reference and source of inspiration for agricultural scientists conducting future research.展开更多
Osteochondral defects involving both articular cartilage and subchondral bone remain challenging in clinical treatment.Inspired by the zonal organization of native osteochondral tissue and the sophisticated architectu...Osteochondral defects involving both articular cartilage and subchondral bone remain challenging in clinical treatment.Inspired by the zonal organization of native osteochondral tissue and the sophisticated architecture of articular cavity,we designed a biomimetic bilayer scaffold system using 3D printing technology.The scaffold recreates the natural structural and mechanical gradients of the osteochondral interface,featuring a gradient transition from cartilage to bone phase.To enhance the bio-functionality of this biomimetic design,we incorporated the small molecule Kartogenin(KGN),which has shown promising potential in cartilage regeneration by promoting chondrogenic differentiation and inhibiting cartilage degeneration.However,the reparative efficacy of KGN is highly concentration-dependent,and the optimal concentration within complex three-dimensional scaffold environments remains unclear.Through both in vitro and in vivo evaluations of this bio-inspired scaffold system loaded with varying KGN concentrations,we identified that 5μM KGN(SCS@K5)achieved optimal outcomes.At 12 weeks,the SCS@K5 treatment resulted in better organized osteochondral tissue with improved interface integration relative to other groups.This biomimetic gradient design incorporating KGN release offers a viable approach for osteochondral defect repair.展开更多
Tissue engineering has advanced remarkably in developing functional tissue substitutes for pharmaceutical and regenerative applications.Among emerging technologies,three-dimensional(3D)printing,or additive manufacturi...Tissue engineering has advanced remarkably in developing functional tissue substitutes for pharmaceutical and regenerative applications.Among emerging technologies,three-dimensional(3D)printing,or additive manufacturing,enables precise fabrication of biocompatible materials,living cells,and scaffolds into complex,viable constructs.Within regenerative medicine,3D bioprinting addresses the growing demand for transplantable tissues and organs by assembling biological materials that replicate native architectures.This paper reviews biomaterials used in 3D bioprinting,emphasizing how their rheological behavior,particularly viscoelasticity and thixotropy,governs printability,structural fidelity,and cellular viability.The advantages and limitations of natural,synthetic,and composite bioinks are analyzed in relation to their mechanical performance and flow properties.In addition,common 3D bioprinting techniques such as extrusion,inkjet,and laser-assisted methods are outlined with reference to their compatibility with various material systems.Recent applications in bone,cartilage,vascular,skin,neural,cardiac,hepatic,and pulmonary tissue engineering are briefly summarized.展开更多
Biodegradable magnesium(Mg)-based medical devices have revolutionized medical implants by uniquely combining biocompatibility and mechanical strength.Fully degradable Mg-based implants have been developed to provide t...Biodegradable magnesium(Mg)-based medical devices have revolutionized medical implants by uniquely combining biocompatibility and mechanical strength.Fully degradable Mg-based implants have been developed to provide temporary structural support and serve as a dynamic scaffold for tissue repair and restructuring.Additionally,Mg-based devices can respond to physiological signals,and their integration with electrical currents or pulses has been explored to enhance tissue healing and functional recovery.This review provides a comprehensive overview of the development and application of Mg-based medical devices,highlighting their evolution from traditional orthopedic,vascular,and dental uses to advanced systems that actively modulate physiological processes—a shift from passive support to active modulation.The application range of Mg-based devices has expanded from early vascular sutures,bone screws,and stents to multiple clinical fields including porous bone repair scaffolds,anastomotic staples,bioactive devices,and electro-active systems.Bioactive Mg devices demonstrate therapeutic properties including antibacterial,anti-inflammatory,anti-tumor,and osteogenic functions through their degradation products,while electro-active devices utilize the electrical properties of Mg for sensing,monitoring,and therapeutic stimulation.Finally,this review highlights current challenges,including maintaining mechanical support performance,optimizing control of biochemical reactions,and balancing electroregulatory functions,and identifies future research directions aimed at enhancing the clinical application of biodegradable Mg-based implants,thereby contributing to the significant advancement in the biomedical field.展开更多
Metallic scaffolds with lightweight,low elastic modulus,and high energy-absorbing capacity are widely utilized in industrial applications but usually require post-heat treatment to enhance their comprehen-sive mechani...Metallic scaffolds with lightweight,low elastic modulus,and high energy-absorbing capacity are widely utilized in industrial applications but usually require post-heat treatment to enhance their comprehen-sive mechanical properties.However,it is unclear how to utilize the impact ofβ-Nb on the surrounding matrix for NiTiNb ternary alloys to achieve strength-ductility-superelasticity enhancement.Here,we pre-pared rhomboidal dodecahedral NiTiNb porous scaffolds with a porosity of 85.9%by additive manufac-turing.Subsequently,annealing treatment was employed to drastically reduce the phase transformation temperatures and expand the thermal hysteresis.Interestingly,the 850℃ annealed scaffold exhibited exceeding double compressive strength of the as-built sample,with a remarkable improvement in ductil-ity and superelasticity.From the microstructure perspective,high-temperature annealing caused a further eutectic reaction of the unmelted Nb particles with the NiTi matrix and the transformation of mesh-likeβ-Nb into dispersedly distributed sphericalβ-Nb particles.The microstructure evolution after defor-mation indicated that stress-induced martensitic transformation occurred in the matrix away from the NiTi-Nb eutectic region whereas almost no martensite formed nearbyβ-Nb particles.Atom probe tomog-raphy characterization revealed an element diffusion zone in several nanometers surrounding theβ-Nb particle,where the substitution of Nb with Ti led to a higher Ni:Ti atomic ratio,lowering transforma-tion temperatures.Molecular dynamics simulations illustrated thatβ-Nb particles can not only entangle dislocations internally,acting as reinforcements but also hinder the twin growth,contributing to strain hardening.This work elucidates the influence ofβ-Nb particles on the deformation mechanism of the NiTi-Nb eutectic region through in-depth atomic-scale investigation,which can provide inspiration for the improvement of comprehensive mechanical properties of NiTiNb alloys.展开更多
文摘EFL preservice teachers ’ research efficacy, as perceived competence to perform tasks in research, is crucial to their research engagement. This autobiographical narrative inquiry investigates the contribution of scaffolded research practice to a female EFL preservice teacher ’s research efficacy.The data were collected through conversations, notes, journals, and portfolios. The findings suggest that teacher research efficacy was pliable through scaffolded research practice. It emerged gradually over time, in different places with social and personal interaction. The factors contributing to the emerging research efficacy were: teacher educators ’ support, peers ’ support,and research participation. The study sheds light on teacher educators and EFL preservice teachers,with the intention of establishing an inquiry-based pedagogy for M.Ed. programs.
基金supported by the National Key R&D Program of China(2016YFA0202602,2016YFA0202603)the National Natural Science Foundation of China(U1663225)+1 种基金the 111 national project(Grant No.B20002)from Ministry of Science and Technologythe Ministry of Education and Sinopec Ministry of Science and Technology Basic Prospective Research Project(218025-9)。
文摘Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of capacitors.Titanium dioxide(TiO_(2)),is a promising anode material.Its performance is however seriously hindered by its low electrical conductivity and the sluggish diffusion of sodium ions(Na^(+))in the TiO_(2)matrix.Herein,this work combines porous TiO_(2)nanocubes with carbon nanotubes(CNTs)to enhance the electrical conductivity and accelerate Na^(+)diffusivity for Na-ion batteries(NIBs).In this composite,an interwoven scaffolded TiO_(2)/CNTs framework is formed to provide abundant channels and shorter diffusion pathways for electrons and ions.The in-situ X-ray diffraction and cyclic voltammetry confirm the low strain and superior transport kinetics in Na^(+)intercalation/extraction processes.In addition,the chemically bonded TiO_(2)/CNTs hybrid provides a more feasible channel for Na^(+)insertion/extraction with a much lower energy barrier.Consequently,the TiO_(2)/CNTs composite exhibits excellent electrochemical performance with a capacity of 223.4 m Ah g^(-1)at 1 C and a capacity of 142.8 m Ah g^(-1)at 10 C(3.35 A g^(-1)).The work here reveals that the combination of active materials with CNTs can largely improve the utilization efficiency and enhance their sodium storage.
基金supported by the Russian state-funded project for ICBFM SB RAS(grant number 125012300656-5)。
文摘Background:The development of materials for cardiovascular surgery that would improve the effectiveness of surgical interventions remains an important task.Surgical intervention during the implantation of vascular prostheses and stents,and the body’s reaction to artificial materials,could lead to chronic inflammation,a local increase in the concentration of proinflammatory factors,and stimulation of unwanted tissue growth.The introduction of nonsteroidal anti-inflammatory drugs into implantable devices could be used to obtain vascular implants that do not induce inflammation and do not induce neointimal tissue outgrowth.Methods:The scaffolds were made by electrospinning from mixtures of polyurethane(PU)with diclofenac(DF).The kinetics of DF release from the scaffolds composed of 3%PU/10%HSA/3%DMSO/DF and 3%PU/DF were studied.The biocompatibility and anti-inflammatory effects of the obtained scaffolds on human gingival fibroblasts and umbilical vein endothelial cells were studied.Results:Both types of scaffolds are characterized by fast DF release.The viability of cells cultured on scaffolds is 2 times worse than that of cells cultured on plastic.The level of the proinflammatory cytokine IL-6 in the culture medium of cells cultured on DF-containing scaffolds was lower than that of cells cultured on scaffolds without DF.Conclusion:The introduction of DF into scaffolds minimizes the inflammation caused by cell reactions to an artificial material.
基金financially supported by the National Natural Science Foundation of China(Nos.82203680 and 52273278)the Natural Scientific Foundation of Liaoning Province(No.2021-MS-176)+1 种基金Shenyang Bureau of Science and Technology(No.RC230527)the Central Guidance Funding for Local Scientific and Techno-logical Development in Liaoning(No.2023JH6/100100029).
文摘Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.
基金Financial support from Beijing Natural Science Foundation(No.7232283)。
文摘From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganumium C(3)were ionic alkaloid salts and peganumium B was a hexacycliccondensed alkaloid.The biosynthetic pathways of the three compounds above were also speculated.A preliminary cytotoxicity assay revealed that peganumium B had strong in vitro antiproliferative ability against a variety of cancer cells.The analysis of^(1)H nuclear magnetic resonance(NMR)metabolomics suggested that the antiproliferative mechanism of peganumium B could be associated with the biosynthesis of phenylalanine,tyrosine and tryptophan,the metabolism of glycine,serine,and threonine,the metabolism of taurine and hypotaurine,and the metabolism of nicotinate and nicotinamide.In addition,peganumium B could reduce the mitochondrial content of body-wall muscle cells of a Caenorhabditis elegans(C.elegans)strain in vivo.
基金supported by National Key R&D Program of China(Grant No.2022YFB4600500)Fundamental Research Funds for the Central Universities,and the Program for Innovation Team of Shaanxi Province(Grant No.2023-CX-TD-17).
文摘Porous designs effectively reduce stress shielding in metallic orthopedic implants.However,current porous structures often fail to adequately meet the needs of patients with osteoporosis and low-modulus body regions.This study proposes a sinusoidal-based lattice structure for an ultralow and widely tunable modulus design,aiming to match diverse bone tissue requirements and enhance biomechanical compatibility.Parametric modeling and finite element analysis were used to evaluate the performance of this structure.Results show that,within the design range suitable for bone growth,the elastic modulus of this lattice structure is tunable over a wide range,from 0.09 to 32.67 GPa,outperforming existing porous structures.The lowest value closely matched the minimum mechanical properties of human cancellous bone among porous structures.Moreover,the structure exhibited distinct anisotropic characteristics,allowing for directional design based on mechanical requirements.The structure’s permeability ranged from 1.19×10^(-8) m^(2) to 2.3×10^(-7) m^(2),making it highly compatible with human cancellous bone and meeting the requirements of orthopedic implants.Samples with porosities ranging from 46% to 87% were successfully fabricated using powder bed fusion additive manufacturing,validating the simulation predictions.This tunable low-modulus lattice structure provides a novel approach for developing personalized orthopedic implants,particularly for patients with specialized needs such as osteoporosis,and can potentially enhance biomechanical compatibility and long-term stability.
基金supported by the Sichuan Science and Technology Program,No.2023YFS0164(to JC)the National Natural Science Foundation of China,No.82401629(to XL)+1 种基金the Natural Science Foundation of Sichuan Province,No.2024NSFSC1646(to XL)the China Postdoctoral Science Foundation,Nos.GZC20231811(to XL)and 2024T170601(to XL)。
文摘Enhancing neurological recovery and improving the prognosis of spinal cord injury have gained research attention recently.Spinal cord injury is associated with a complex molecular and cellular microenvironment.This complexity has prompted researchers to elucidate the underlying pathophysiological mechanisms and changes and to identify effective treatment strategies.Traditional approaches for spinal cord injury repair include surgery,oral or intravenous medications,and administration of neurotrophic factors;however,the efficacy of these approaches remains inconclusive,and serious adverse reactions continue to be a concern.With advancements in tissue engineering and regenerative medicine,emerging strategies for spinal cord injury repair now involve nanoparticle-based nanodelivery systems,scaffolds,and functional recovery techniques that incorporate biomaterials,bioengineering,stem cell,and growth factors as well as three-dimensional bioprinting.Ideal biomaterial scaffolds should not only provide structural support for neuron migration,adhesion,proliferation,and differentiation but also mimic the mechanical properties of natural spinal cord tissue.Additionally,these scaffolds should facilitate axon growth and neurogenesis by offering adjustable topography and a range of physical and biochemical cues.The three-dimensionally interconnected porous structure and appropriate physicochemical properties enabled by three-dimensional biomimetic printing technology can maximize the potential of biomaterials used for treating spinal cord injury.Therefore,correct selection and application of scaffolds,coupled with successful clinical translation,represent promising clinical objectives to enhance the treatment efficacy for and prognosis of spinal cord injury.This review elucidates the key mechanisms underlying the occurrence of spinal cord injury and regeneration post-injury,including neuroinflammation,oxidative stress,axon regeneration,and angiogenesis.This review also briefly discusses the critical role of nanodelivery systems used for repair and regeneration of injured spinal cord,highlighting the influence of nanoparticles and the factors that affect delivery efficiency.Finally,this review highlights tissue engineering strategies and the application of biomaterial scaffolds for the treatment of spinal cord injury.It discusses various types of scaffolds,their integrations with stem cells or growth factors,and approaches for optimization of scaffold design.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82173699 and 32200531)Shanghai Jiao Tong University Trans-Med Awards Research,China(STAR Project No.:20230101)Shanghai Science and Technol-ogy Commission,China(Grant No.:23DZ2290600).
文摘Numerous c-mesenchymal-epithelial transition(c-MET)inhibitors have been reported as potential anticancer agents.However,most fail to enter clinical trials owing to poor efficacy or drug resistance.To date,the scaffold-based chemical space of small-molecule c-MET inhibitors has not been analyzed.In this study,we constructed the largest c-MET dataset,which included 2,278 molecules with different struc-tures,by inhibiting the half maximal inhibitory concentration(IC_(50))of kinase activity.No significant differences in drug-like properties were observed between active molecules(1,228)and inactive mol-ecules(1,050),including chemical space coverage,physicochemical properties,and absorption,distri-bution,metabolism,excretion,and toxicity(ADMET)profiles.The higher chemical diversity of the active molecules was downscaled using t-distributed stochastic neighbor embedding(t-SNE)high-dimensional data.Further clustering and chemical space networks(CSNs)analyses revealed commonly used scaffolds for c-MET inhibitors,such as M5,M7,and M8.Activity cliffs and structural alerts were used to reveal“dead ends”and“safe bets”for c-MET,as well as dominant structural fragments consisting of pyr-idazinones,triazoles,and pyrazines.Finally,the decision tree model precisely indicated the key structural features required to constitute active c-MET inhibitor molecules,including at least three aromatic het-erocycles,five aromatic nitrogen atoms,and eight nitrogeneoxygen atoms.Overall,our analyses revealed potential structure-activity relationship(SAR)patterns for c-MET inhibitors,which can inform the screening of new compounds and guide future optimization efforts.
基金supported by the National Natural Science Foundation of China(Nos.51975400 and 62031022)the Shanxi Provincial Key Medical Scientific Research Project(No.2020XM06)+2 种基金the Shanxi Provincial Basic Research Project(Nos.202103021221006,20210302123040,and 202103021223069)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2021L044)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD026).
文摘Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis.However,the healed skin tissue often exhibits abnormal morphology and functionality,including scarring and inflammation.In this study,a composite bioink composed of methacrylated gelatin(GelMA)and chitosan oligosaccharide(COS)was proposed for printing a dermal scaffold using digital light processing(DLP)technology.The GelMA/COS bioink exhibited suitable porosity,swelling,degradation rate,and mechanical properties.The inclusion of COS demonstrated antibacterial effects against both Gram positive and Gram-negative bacteria,while simultaneously fostering the proliferation of human dermal fibroblasts(HDFs).Additionally,the application of COS could effectively reduce the expression levels of fibrosis-related genes,such as collagen I,collagen III,and fibronectin I.The three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability,facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix proteins.Furthermore,the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure,reduce inflammation,and improve wound healing.Overall,the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.
基金supported by the National Natural Science Foundation of China(No.82272297).
文摘Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomimetic scaffold aimed at facilitating rapid and scarless wound healing.This highly in-tegrated 3D-printed dermal scaffold comprised modified recombinant human type III collagen(rhCOLIII-MA),gelatin methacrylate(GelMA),and liposomes encapsulating SB431542 to target TGF-β1(Lip@SB).The rhCOLIII-MA/GelMA(CG)scaffold retained inherent biomaterial characteristics,exhibited tailored physicochemical properties,and demonstrated favorable biocompatibility.Moreover,the Lip@SB-loaded CG scaffold(CGL)effectively promoted in vitro wound healing,while enabling controlled release of SB431542 to inhibit pathological collagen deposition.In a full-thickness skin defect rat model,the CGL dermal scaffold combined with split-thickness skin graft(STSG)minimized scar contraction,stimulated functional neovascularization,and enhanced graft aesthetics comparable to normal skin.Remarkably,the performance of the CGL scaffold surpassed that of commercially available anti-scarring alternatives.This innovative strategy presents a straightforward approach toward scarless skin regeneration and holds promise in alleviating the prolonged,painful postoperative rehabilitation.
基金supported by the National Natural Science Foundation of China(Grant No.52473121,52403370 and 52221006)Fundamental Research Funds for the Central Universities(buctrc202020,buctrc202312).
文摘The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.
基金the National Key Research and Development Program of China(Grant No.2023YFC2412600)the National Natural Science Foundation of China(Grant No.51971171)for financially supporting this work.
文摘Current modifications of Ti-based materials with porous scaffolds for achieving biological fixation often decrease corrosion fatigue strength(σ_(cf))of the resultant implants,thereby shortening their service lifes-pan.To resolve this issue,in the present,a step-wise graded porous Ti-6Al-7Nb scaffold was additively manufactured on optimally surface mechanical attrition treated(SMATed)Ti-6Al-7Nb(specifically de-noted as S-Ti6Al7Nb)using laser powder bed fusion(PBF)technology.The microstructure,bond strength,residual stress distribution,and corrosion fatigue behavior of porous scaffolds modified S-Ti6Al7Nb were investigated and compared with those of mechanically polished Ti-6Al-7Nb(P-Ti6Al7Nb),S-Ti6Al7Nb,and porous scaffolds modified P-Ti6Al7Nb.Results showed that corrosion fatigue of porous scaffolds modi-fied Ti-6Al-7Nb was propagation controlled.Moreover,the crack propagation behavior in the PBF scaf-fold’s fusion zone(FZ)and heat-affected zone(HAZ),exhibiting insensitivity to the microstructural con-figurations characterized by columnar prior-βgrain(PBG)boundaries and acicularα''martensites,cou-pled with the PBF-induced residual tensile stresses in these regions,resulted in a considerable decrease inσ_(cf) for porous scaffolds modified P-Ti6Al7Nb compared to P-Ti6Al7Nb.In contrast,step-wise graded porous scaffold-modified S-Ti6Al7Nb demonstrated an improvedσ_(cf) which was even higher than that of P-Ti6Al7Nb.Such an advancement in corrosion fatigue strength is primarily attributed to the presence of residual compressive stresses within the underlying S-Ti6Al7Nb substrate,extending beyond FZ and HAZ.These stresses increased the crack propagation threshold,leading to crack deflection/branching and increased crack-path tortuosity,thereby synergistically markedly enhancing the crack propagation resis-tance of porous scaffolds modified S-Ti6Al7Nb.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
文摘Introduction It is necessary for an ideal bioceramic scaffold to have a suitable structure.The structure can affect the mechanical properties of the scaffold(i.e.,elastic modulus and compressive strength)and the biological properties of the scaffold(i.e.,degradability and cell growth rate).Lattice structure is a kind of periodic porous structure,which has some advantages of light weight and high strength,and is widely used in the preparation of bioceramic scaffolders.For the structure of the scaffold,high porosity and large pore size are important for bone growth,bone integration and promoting good mechanical interlocking between neighboring bones and the scaffold.However,scaffolds with a high porosity often lack mechanical strength.In addition,different parts of the bone have different structural requirements.In this paper,scaffolds with a non-uniform structure or a hierarchical structure were designed,with loose and porous exterior to facilitate cell adhesion,osteogenic differentiation and vascularization as well as relatively dense interior to provide sufficient mechanical support for bone repair.Methods In this work,composite ceramics scaffolds with 10%akermanite content were prepared by DLP technology.The scaffold had a high porosity outside to promote the growth of bone tissue,and a low porosity inside to withstand external forces.The compressive strength,fracture form,in-vitro degradation performance and bioactivity of graded bioceramic scaffolds were investigated.The models of scaffolds were imported into the DLP printer with a 405 nm light.The samples were printed with the intensity of 8 mJ/cm^(2)and a layer thickness of 50μm.Finally,the ceramic samples were sintered at 1100℃.The degradability of the hierarchical gyroid bioceramic scaffolds was evaluated through immersion in Tris-HCl solution and SBF solution at a ratio of 200 mL/g.The bioactivity of bioceramic was obtained via immersing them in SBF solution for two weeks.The concentrations of calcium,phosphate,silicon,and magnesium ions in the soaking solution were determined by an inductively coupled plasma optical emission spectrometer.Results and discussion In this work,a hierarchical Gyroid structure HA-AK10 scaffold(sintered at 1100℃)with a radial internal porosity of 50%and an external porosity of 70%is prepared,and the influence of structural form on the compressive strength and degradation performance of the scaffold is investigated.The biological activity of the bioceramics in vitro is also verified.The mechanical simulation results show that the stress distribution corresponds to the porosity distribution of the structure,and the low porosity is larger and the overall stress concentration phenomenon does not appear.After soaking in SBF solution,Si—OH is firstly formed on the surface of bioceramics,and then silicon gel layer is produced due to the presence of calcium and silicon ions.The silicon gel layer is dissociated into negatively charged groups under alkaline environment secondary adsorption of calcium ions and phosphate ions,forming amorphous calcium phosphate,and finally amorphous calcium phosphate crystals and adsorption of carbonate ions,forming carbonate hydroxyapatite.This indicates that the composite bioceramics have a good biological activity in-vitro and can provide a good environment for the growth of bone cells.A hierarchical Gyroid ceramic scaffold with a bone geometry is prepared via applying the hierarchical structure to the bone contour scaffold.The maximum load capacity of the hierarchical Gyroid ceramic scaffold is 8 times that of the uniform structure.Conclusions The hierarchical structure scaffold designed had good overall compressive performance,good degradation performance,and still maintained a good mechanical stability during degradation.In addition,in-vitro biological experimental results showed that the surface graded composite scaffold could have a good in-vitro biological activity and provide a good environment for bone cells.Compared to the heterosexual structure,the graded scaffold had greater mechanical properties.
基金Science and Technology Planning Project of Inner Mongolia Science and Technology Department(2022YFSH0021)Key Research and Development Program of Shaanxi Province(2024SF2-GJHX-14,2021SF-296)。
文摘Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser melting.Their forming quality,compression mechanical properties,and degradation behavior were investigated.Results indicate that the fabricated scaffolds exhibit good dimensional accuracy,and the surface chemical polishing treatment significantly improves the forming quality and reduces porosity error in porous scaffolds.Compared to the ones with rod structures(bcc,RD),the scaffolds with surface structures(G,P)have less powder particle adhesion.The G porous scaffold exhibits the best forming quality for the same design porosity.The predominant failure mode of scaffolds during compression is a 45°shear fracture.At a porosity of 75%,the compression property of all scaffolds meets the compressive property requirements of cancellous bone,while bcc and G structures show relatively better compression property.After immersion in Hank's solution for 168 h,the B-2-75% pore structure scaffold exhibits severe localized corrosion,with fractures in partial pillar connections.In contrast,the G-3-75% pore structure scaffold mainly undergoes uniform corrosion,maintaining structural integrity,and its corrosion rate and loss of compressive properties are less than those of the B-2-75%structure.After comparison,the G-pore structure scaffold is preferred.
基金the financial support from the National Key Research and Development Program of China(No.2021YFD1700102)the National Natural Science Foundation of China(No.32472608)+3 种基金the Guizhou Provincial Fundation for Excellent Scholars Program(No.GCC[2023]069)the Central Government Guides Local Science and Technology Development Fund Projects(No.Qiankehezhongyindi[2024]007)the Guizhou Province Program of Major Scientific and Technological(No.Qiankehechengguo[2024]zhongda007)the Central Government Guides Local Science and Technology Development Fund Projects(No.Qiankehezhongyindi(2023)001)。
文摘Pyridazine has garnered increasing attention as a privileged scaffold and bioisosterism in drug discovery due to its unique structural characteristics.It can serve as a hydrogen bond acceptor when interacting with receptors due to its two adjacent nitrogen atoms.Upon conversion to pyridazinone,it exhibits the ability to act as both a hydrogen bond acceptor and donor,showcasing its versatility.This inherent flexibility has prompted extensive research exploring its bioactivity in pesticides and pharmaceuticals.In order to promote the development of pyridazine-based pesticides,this review provides a comprehensive summary of advancements for pyridazine-based pesticides on herbicidal(36.9%),insecticidal(26.2%),antifungal and antibacterial(24.6%),plant growth regulatory(10.8%),and antiviral activities(1.5%)from2000 to 2024.It serves as an invaluable reference and source of inspiration for agricultural scientists conducting future research.
基金supported by the National Key Research and Development Program of China(2022YFE0107700)the Joint Fund Project of the National Natural Science Foundation of China(U23A20523)the General Program of the National Natural Science Foundation of China(8247092827).
文摘Osteochondral defects involving both articular cartilage and subchondral bone remain challenging in clinical treatment.Inspired by the zonal organization of native osteochondral tissue and the sophisticated architecture of articular cavity,we designed a biomimetic bilayer scaffold system using 3D printing technology.The scaffold recreates the natural structural and mechanical gradients of the osteochondral interface,featuring a gradient transition from cartilage to bone phase.To enhance the bio-functionality of this biomimetic design,we incorporated the small molecule Kartogenin(KGN),which has shown promising potential in cartilage regeneration by promoting chondrogenic differentiation and inhibiting cartilage degeneration.However,the reparative efficacy of KGN is highly concentration-dependent,and the optimal concentration within complex three-dimensional scaffold environments remains unclear.Through both in vitro and in vivo evaluations of this bio-inspired scaffold system loaded with varying KGN concentrations,we identified that 5μM KGN(SCS@K5)achieved optimal outcomes.At 12 weeks,the SCS@K5 treatment resulted in better organized osteochondral tissue with improved interface integration relative to other groups.This biomimetic gradient design incorporating KGN release offers a viable approach for osteochondral defect repair.
文摘Tissue engineering has advanced remarkably in developing functional tissue substitutes for pharmaceutical and regenerative applications.Among emerging technologies,three-dimensional(3D)printing,or additive manufacturing,enables precise fabrication of biocompatible materials,living cells,and scaffolds into complex,viable constructs.Within regenerative medicine,3D bioprinting addresses the growing demand for transplantable tissues and organs by assembling biological materials that replicate native architectures.This paper reviews biomaterials used in 3D bioprinting,emphasizing how their rheological behavior,particularly viscoelasticity and thixotropy,governs printability,structural fidelity,and cellular viability.The advantages and limitations of natural,synthetic,and composite bioinks are analyzed in relation to their mechanical performance and flow properties.In addition,common 3D bioprinting techniques such as extrusion,inkjet,and laser-assisted methods are outlined with reference to their compatibility with various material systems.Recent applications in bone,cartilage,vascular,skin,neural,cardiac,hepatic,and pulmonary tissue engineering are briefly summarized.
文摘Biodegradable magnesium(Mg)-based medical devices have revolutionized medical implants by uniquely combining biocompatibility and mechanical strength.Fully degradable Mg-based implants have been developed to provide temporary structural support and serve as a dynamic scaffold for tissue repair and restructuring.Additionally,Mg-based devices can respond to physiological signals,and their integration with electrical currents or pulses has been explored to enhance tissue healing and functional recovery.This review provides a comprehensive overview of the development and application of Mg-based medical devices,highlighting their evolution from traditional orthopedic,vascular,and dental uses to advanced systems that actively modulate physiological processes—a shift from passive support to active modulation.The application range of Mg-based devices has expanded from early vascular sutures,bone screws,and stents to multiple clinical fields including porous bone repair scaffolds,anastomotic staples,bioactive devices,and electro-active systems.Bioactive Mg devices demonstrate therapeutic properties including antibacterial,anti-inflammatory,anti-tumor,and osteogenic functions through their degradation products,while electro-active devices utilize the electrical properties of Mg for sensing,monitoring,and therapeutic stimulation.Finally,this review highlights current challenges,including maintaining mechanical support performance,optimizing control of biochemical reactions,and balancing electroregulatory functions,and identifies future research directions aimed at enhancing the clinical application of biodegradable Mg-based implants,thereby contributing to the significant advancement in the biomedical field.
基金financial supports of National Natural Science Foundation of China under Grant Nos.52274387 and 52311530772.
文摘Metallic scaffolds with lightweight,low elastic modulus,and high energy-absorbing capacity are widely utilized in industrial applications but usually require post-heat treatment to enhance their comprehen-sive mechanical properties.However,it is unclear how to utilize the impact ofβ-Nb on the surrounding matrix for NiTiNb ternary alloys to achieve strength-ductility-superelasticity enhancement.Here,we pre-pared rhomboidal dodecahedral NiTiNb porous scaffolds with a porosity of 85.9%by additive manufac-turing.Subsequently,annealing treatment was employed to drastically reduce the phase transformation temperatures and expand the thermal hysteresis.Interestingly,the 850℃ annealed scaffold exhibited exceeding double compressive strength of the as-built sample,with a remarkable improvement in ductil-ity and superelasticity.From the microstructure perspective,high-temperature annealing caused a further eutectic reaction of the unmelted Nb particles with the NiTi matrix and the transformation of mesh-likeβ-Nb into dispersedly distributed sphericalβ-Nb particles.The microstructure evolution after defor-mation indicated that stress-induced martensitic transformation occurred in the matrix away from the NiTi-Nb eutectic region whereas almost no martensite formed nearbyβ-Nb particles.Atom probe tomog-raphy characterization revealed an element diffusion zone in several nanometers surrounding theβ-Nb particle,where the substitution of Nb with Ti led to a higher Ni:Ti atomic ratio,lowering transforma-tion temperatures.Molecular dynamics simulations illustrated thatβ-Nb particles can not only entangle dislocations internally,acting as reinforcements but also hinder the twin growth,contributing to strain hardening.This work elucidates the influence ofβ-Nb particles on the deformation mechanism of the NiTi-Nb eutectic region through in-depth atomic-scale investigation,which can provide inspiration for the improvement of comprehensive mechanical properties of NiTiNb alloys.
