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
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
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
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
Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this stud...Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.展开更多
In clinical practice,the irregular shapes of traumas pose a significant challenge in rapidly manufacturing personalized scaffolds.To address these challenges,inspired by LEGO■ bricks,this study proposed a novel conce...In clinical practice,the irregular shapes of traumas pose a significant challenge in rapidly manufacturing personalized scaffolds.To address these challenges,inspired by LEGO■ bricks,this study proposed a novel concept of modular scaffolds and developed an innovative system based on machine vision for their rapid and intelligent assembly tailored to defect shapes.Trapezoidal interfaces effectively connect standardized bone units based on magnesium-doped silicate calcium,ensuring high stability of the modular scaffolds,with compressive strength up to 135 MPa and bending strength up to 17 MPa.Through self-developed defect recognition and reconstruction algorithms,defect recognition and personalized assembly schemes for bone scaffolds can be achieved autonomously.Modular scaffolds seamlessly integrate with surrounding bone tissue,promoting new bone growth,with no apparent differences compared to fully 3D printed integral scaffolds in the skull and femur repair experiments.In summary,the adoption of modular scaffolds not only integrates personalization and standardization but also satisfies the optimal treatment window.展开更多
Natural bones exhibit a substantial recoverable strain(ε_(rec))of 2%-4%and vary in mechanical and mass transfer properties across different body regions.Integrating these attributes is essential for the functionality...Natural bones exhibit a substantial recoverable strain(ε_(rec))of 2%-4%and vary in mechanical and mass transfer properties across different body regions.Integrating these attributes is essential for the functionality and therapeutic efficacy of metallic scaffolds used in bone defect treatment.This study presents innovative superelastic nickel-titanium(NiTi)scaffolds with a remarkable maximumε_(rec)of 6%-7%and extensive tuneability in elastic modulus,cyclic stress,compressive strength,specific damping capacity,and permeability.These impressive performance integrations are attributed to carefully designed structures featuring stable austenite phases with hierarchical micro structures and gyroid-sheet macro structures.Physical experiments and computational simulations illustrate that this unique structure combination promotes martensitic transformation during deformation and allows the tuning of mechanical and mass transfer properties without compromising superelasticity.The deformationrecoverable and performance-tuneable NiTi scaffolds are more adaptive than their conventional counterparts,offering a versatile solution for diverse bone implantation needs.In addition to scaffold applications,this study provides valuable insights for developing advanced multifunctional metamaterials applicable in other fields.展开更多
Porous metals fabricated via three-dimensional(3D)printing have attracted extensive attention in many fields owing to their open pores and customization potential.However,dense internal structures produced by the powd...Porous metals fabricated via three-dimensional(3D)printing have attracted extensive attention in many fields owing to their open pores and customization potential.However,dense internal structures produced by the powder bed fusion technique fails to meet the feature of porous materials in scenarios that demand large specific surface areas.Herein,we propose a strategy for 3D printing of titanium scaffolds featuring multiscale porous internal structures via powder modification and digital light processing(DLP).After modification,the titanium powders were composited with acrylic resin and maintained spherical shapes.Compared with the raw powder slurries,the modified powder slurries exhibited higher stability and preferable curing characteristics,and the depth sensitivity of the modified powder slurries with 45 vol%solid loading increased by approximately 72%.Green scaffolds were subsequently printed from the slurries with a solid loading reaching 45 vol%via DLP 3D printing.The scaffolds had macropores(pore diameters of approximately 1 mm)and internal open micropores(pore diameters of approximately 5.7-13.0μm)after sintering.Additionally,these small-featured(approximately 320μm)scaffolds retained sufficient compressive strength((70.01±3.53)MPa)even with high porosity(approximately 73.95%).This work can facilitate the fabrication of multiscale porous metal scaffolds with high solid loading slurries,offering potential for applications requiring high specific surface area ratios.展开更多
The esophagus is an important part of the human digestive system.Due to its limited regenerative capacity and the infeasibility of donor transplantation,esophageal replacement has become an important problem to be sol...The esophagus is an important part of the human digestive system.Due to its limited regenerative capacity and the infeasibility of donor transplantation,esophageal replacement has become an important problem to be solved urgently in clinics.In recent years,with the rapid development of tissue engineering technology in the biomedical field,tissue engineering stent(artificial esophagus)provides a new therapeutic approach for the repair and reconstruction of esophageal defects and has made remarkable progress.Biomedical esophageal stent materials have also experienced the development process from non-absorbable materials to absorbable materials,and then to new materials with composite cells and biological factors.In this paper,the composition,functional characteristics,and limitations of non-degradable scaffolds,biodegradable scaffolds,and Decellularized Matrix(DM)scaffolds specially designed for these applications are reviewed.Non-absorbable stents are typically composed of synthetic polymers or metals that provide structural support but fail to bind to surrounding tissues over time.In contrast,biodegradable stents are designed to break down gradually in the body while promoting cell infiltration and promoting new tissue formation.DM scaffolds can alleviate autoimmune reactions,preserve natural tissue characteristics,and enable recellularization during auto-repair.In addition,the significance of various cell-loaded materials in esophageal replacement has been explored,and the inclusion of cells in scaffold design has been shown to have the potential to enhance integration with host tissue and improve postoperative functional outcomes.These advances underscore ongoing efforts to closely mimic the structure of the natural esophagus.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
The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two ...The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.展开更多
The treatment of prolonged inflammation and cartilage damage due to osteoarthritis(OA)is a major clinical challenge.We developed a comprehensive cartilage repair therapy using a dual drug-loaded nanocomposite hydrogel...The treatment of prolonged inflammation and cartilage damage due to osteoarthritis(OA)is a major clinical challenge.We developed a comprehensive cartilage repair therapy using a dual drug-loaded nanocomposite hydrogel that leveraged the spatiotemporal immunomodulatory effects of a naturally degradable protein-based nanocomposite hydrogel.The hydrogel acted as a scaffold that created a favorable microenvironment for cartilage regeneration.The hydrogel recruited macrophages and human mesenchymal stem cells(hMSCs),which supported the growth and adhesion of osteoblasts,and degraded to provide nutrition.Silk protein nanoparticles were chemically cross-linked with kartogenin,and humanlike collagen was physically cross-linked with dexamethasone through hydrogen bonding.In the early stages of cartilage repair,a large quantity of dexamethasone was released.The dexamethasone acted as an anti-inflammatory agent and a spatiotemporal modulator of the polarization of M1 macrophages into M2 macrophages.In the middle and late stages of cartilage repair,kartogenin underwent sustained release from the hydrogel,inducing the differentiation of hMSCs into chondrocytes and maintaining chondrocyte stability.Therefore,kartogenin and dexamethasone acted synergistically to induce cartilage repair.In conclusion,we developed an integrated therapeutic system by constructing a cartilage regeneration microenvironment and inducing synergistic drug-based cartilage regeneration.The therapeutic system demonstrated satisfactory efficacy for repairing cartilage damage in rabbits.展开更多
Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO...Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser sintering.The results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in vitro.Antibacterial experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus aureus.Finally,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.展开更多
In bone tissue engineering,scaffold design must achieve specific mechanical compatibility with implantation sites,critically determining implant performance.This study developed four cylindrical Ti6Al4V bone scaffolds...In bone tissue engineering,scaffold design must achieve specific mechanical compatibility with implantation sites,critically determining implant performance.This study developed four cylindrical Ti6Al4V bone scaffolds via selective laser melting(SLM),incorporating distinct lattice architectures:Face-Centered Cubic(FCC),Body-Centered Cubic(BCC),Glass Sponge(GS),and Auxetic Structures(AS).Integrated experimental characterization and finite element simulations revealed exceptional mechanical superiority of FCC scaffolds,demonstrating 7-fold greater maximum stress compared to BCC,GS,and AS counterparts.Furthermore,FCC scaffolds exhibited optimal performance metrics including plateau stress(1.2-1.4 GPa),densification strain(0.15-0.25),energy absorption(85-100 MJ/m^(3)),and specific energy absorption(45-55 kJ/kg).These findings confirm that the unique energy dissipation mechanisms inherent to FCC lattice geometry significantly enhance energy absorption efficiency.The study provides a theoretical foundation for developing mechanically adaptive bone implants,particularly advancing clinical applications requiring enhanced energy absorption capabilities.展开更多
Although Ti scaffolds offer great potential in orthopedic applications,their porous nature raises new questions,such as low relative density and high surface area.This work investigated the gradual decrease in the str...Although Ti scaffolds offer great potential in orthopedic applications,their porous nature raises new questions,such as low relative density and high surface area.This work investigated the gradual decrease in the strength of Ti scaffolds during longterm immersion in Hank’s solution.After 180-day immersion,the samples have a 23.3% and 26.6% reduction in yield strength and a 9.0% and 11.2% reduction in compressive strength in dynamic and static solutions,indicating potential failure during the long-term service.A large exposure area to the solution leads to a high corrosion rate,which results in the consumption of the scaffolds and,consequently,decreased strength.Although the covered deposits on the scaffolds reduce the ion release to some extent,the scaffolds still have a slowly ongoing decrease in strength.Based on the durability considerations,some methods,such as decreasing porosity and surface treatments,are proposed to alleviate this phenomenon of Ti scaffolds.展开更多
Scaffolds that emulate the architecture of human bone,combined with strong mechanical stability and biocompatibility,are vital for promoting effective bone tissue regeneration.However,most existing bone-mimetic scaffo...Scaffolds that emulate the architecture of human bone,combined with strong mechanical stability and biocompatibility,are vital for promoting effective bone tissue regeneration.However,most existing bone-mimetic scaffolds fall short in reproducing the intricate hierarchical structure of human bone,which restricts their practical application.This study introduces a novel strategy that combines rotational three-dimensional(3D)printing technology and sponge replication technique to fabricate bone-mimetic scaffolds based on composite materials comprising copper-substituted diopside and biphasic calcium phosphate.The scaffolds closely mimic the structure of human bone,featuring both cancellous and cortical bone with Haversian canals.Additionally,the scaffolds exhibit high porosity and transport capacity,while exhibiting compressive strength that is on par with human bone under both axial and lateral loads.Moreover,they demonstrate good biocompatibility and the potential to induce and support osteogenesis and angiogenesis.The scaffolds produced here present a pathway to remediating particularly large bone defects.Given their close resemblance to human bone structure and function,these scaffolds may be well-suited for developing in vitro bone disease models for pharmaceutical testing and various biomedical applications.展开更多
Recent advances in bone regeneration have introduced the concept of four-dimensional(4D)scaffolds that can undergo morphological and functional changes in response to external stimuli.While several studies have propos...Recent advances in bone regeneration have introduced the concept of four-dimensional(4D)scaffolds that can undergo morphological and functional changes in response to external stimuli.While several studies have proposed patient-specific designs for defect sites,they often fail to adequately distinguish the advantages of 4D scaffolds over conventional 3D counterparts.This study aimed to investigate the potential benefits of 4D scaffolds in clinically challenging scenarios involving curved defects,where fixation is difficult.We proposed the use of Shape-Memory Polymers(SMPs)as a solution to address critical issues in personalized scaffold fabrication,including dimensional accuracy,measurement error,and manufacturing imprecision.Experimental results demonstrated that the Curved-Layer Fused Deposition Modeling(CLFDM)scaffold,which offers superior conformability to curved defects,achieved significantly higher interfacial contact with the defect area compared to traditional Fused Deposition Modeling(FDM)scaffolds.Specifically,the CLFDM scaffold facilitated bone regeneration of 25.59±4.72 mm^(3),which is more than twice the 9.37±1.36 mm^(3)observed with the 3D FDM scaffold.Furthermore,the 4D CLFDM scaffold achieved 75.38±11.65 mm^(3)of new bone formation after four weeks,approximately three times greater than that of the 3D CLFDM scaffold,regardless of surface micro-roughness.These results underscore that improved geometrical conformity between the scaffold and the defect site enhances cellular infiltration and contributes to more effective bone regeneration.The findings also highlight the promise of 4D scaffolds as a compelling strategy to overcome geometric and dimensional mismatches in the design of patient-specific scaffolds.展开更多
In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through top...In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.展开更多
Articular cartilage,which plays a vital role in joint structure,is susceptible to damage from trauma and degenerative joint diseases.Traditional methods for cartilage treatment often involve complex surgical procedure...Articular cartilage,which plays a vital role in joint structure,is susceptible to damage from trauma and degenerative joint diseases.Traditional methods for cartilage treatment often involve complex surgical procedures with limited efficacy.Alternatively,implantable drug-loaded scaffolds are an increasingly attractive cartilage treatment option.To address the challenges of structural and functional compatibility between scaffolds and native cartilage,as well as issues related to drug loading,we design a novel cartilage scaffold with a four-region hollow porous fiber network structure.Using an extrusion-based 3D printing platform,a biphasic silicone ink composed primarily of liquid-phase silicone and solid particles was employed to construct the hollow porous fiber network.Mechanical compression tests demonstrate that the cartilage scaffold has mechanical characteristics similar to those of native cartilage tissue,and ultraviolet spectrophotometry measurements confirm its ability to control drug release.These results showcase the feasibility and effectiveness of the proposed cartilage substitute structure.展开更多
Poly-ether-ether-ketone/nano-silicon nitride(PEEK/nSN)composite scaffolds,fabricated by laser powder bed fusion(LPBF),show great potential for orthopedic applications due to their excellent biological performance and ...Poly-ether-ether-ketone/nano-silicon nitride(PEEK/nSN)composite scaffolds,fabricated by laser powder bed fusion(LPBF),show great potential for orthopedic applications due to their excellent biological performance and mechanical adaptability.However,the effect of nSN on LPBF processability and scaffold properties remains unclear.This study systematically investigates the processability and mechanical per-formance of PEEK/nSN composites to enable reliable clinical fabrication.The results show that adding nSN improves powder flowability and inhibits crystallization,enhancing LPBF processability.The introduction of nSN reduces PEEK’s non-isothermal crystallization Avrami exponent from 3.04 to 2.01,suggesting a transformation from a three-dimensional spherulitic to a two-dimensional lamellar crystal structure.Tensile tests reveal that the presence of nSN alters the optimal process parameters,reducing the optimal laser power from 25 W to 22 W due to increased energy absorption efficiency,as shown by an increase in absorbance at 843 cm^(-1)from 0.27 to 0.35 as the nSN content increases to 2 wt%.Porous diamond-structured scaffolds were fabricated using optimal parameters for pure PEEK,PEEK/1 wt%nSN,and PEEK/2 wt%nSN.Diamond-structured scaffolds fabricated with 1 wt%nSN showed a 12.2%increase in elastic modulus compared to pure PEEK,highlighting the enhanced mechanical performance.Over-all,this study offers key insights into the stable and customizable LPBF fabrication of PEEK/nSN porous scaffolds,providing a foundation for future research on their bioactivity and antibacterial properties for orthopedic applications.展开更多
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.
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.
基金supported by Project of Zhongyuan Critical Metals Laboratory(GJJSGFYQ202406)National Natural Science Foundation of China(51701184,51671175)Young Backbone Teachers Foundation of Zhengzhou University.
文摘Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LY22E050011)National Natural Science Foundation of China(T2121004,51805475)。
文摘In clinical practice,the irregular shapes of traumas pose a significant challenge in rapidly manufacturing personalized scaffolds.To address these challenges,inspired by LEGO■ bricks,this study proposed a novel concept of modular scaffolds and developed an innovative system based on machine vision for their rapid and intelligent assembly tailored to defect shapes.Trapezoidal interfaces effectively connect standardized bone units based on magnesium-doped silicate calcium,ensuring high stability of the modular scaffolds,with compressive strength up to 135 MPa and bending strength up to 17 MPa.Through self-developed defect recognition and reconstruction algorithms,defect recognition and personalized assembly schemes for bone scaffolds can be achieved autonomously.Modular scaffolds seamlessly integrate with surrounding bone tissue,promoting new bone growth,with no apparent differences compared to fully 3D printed integral scaffolds in the skull and femur repair experiments.In summary,the adoption of modular scaffolds not only integrates personalization and standardization but also satisfies the optimal treatment window.
基金supported by the RGC Theme-based Research Scheme Ao E/M-402/20National Natural Science Foundation of China/Hong Kong Research Grants Council Joint Research Scheme(Project No.N_City U151/23)+3 种基金Hong Kong JLFSRGC-Joint Laboratory Funding Scheme(Grant No.JLFS/E102/24)Guangdong Province Science and Technology Plan Project 2023B1212120008Shenzhen Science and Technology Project(Project No:ZDSYS201602291653165)the IMR-City U Joint Laboratory of Nanomaterials&Nanomechanics and Guangdong-Hong Kong Joint Laboratory of Modern Surface Engineering Technology。
文摘Natural bones exhibit a substantial recoverable strain(ε_(rec))of 2%-4%and vary in mechanical and mass transfer properties across different body regions.Integrating these attributes is essential for the functionality and therapeutic efficacy of metallic scaffolds used in bone defect treatment.This study presents innovative superelastic nickel-titanium(NiTi)scaffolds with a remarkable maximumε_(rec)of 6%-7%and extensive tuneability in elastic modulus,cyclic stress,compressive strength,specific damping capacity,and permeability.These impressive performance integrations are attributed to carefully designed structures featuring stable austenite phases with hierarchical micro structures and gyroid-sheet macro structures.Physical experiments and computational simulations illustrate that this unique structure combination promotes martensitic transformation during deformation and allows the tuning of mechanical and mass transfer properties without compromising superelasticity.The deformationrecoverable and performance-tuneable NiTi scaffolds are more adaptive than their conventional counterparts,offering a versatile solution for diverse bone implantation needs.In addition to scaffold applications,this study provides valuable insights for developing advanced multifunctional metamaterials applicable in other fields.
基金supported by the National Natural Science Foundation of China(Nos.52405326,52105588 and 52075421)the Key Research and Development Program of Shaanxi(Nos.2024GX-YBXM-222 and 2023-YBSF-276)。
文摘Porous metals fabricated via three-dimensional(3D)printing have attracted extensive attention in many fields owing to their open pores and customization potential.However,dense internal structures produced by the powder bed fusion technique fails to meet the feature of porous materials in scenarios that demand large specific surface areas.Herein,we propose a strategy for 3D printing of titanium scaffolds featuring multiscale porous internal structures via powder modification and digital light processing(DLP).After modification,the titanium powders were composited with acrylic resin and maintained spherical shapes.Compared with the raw powder slurries,the modified powder slurries exhibited higher stability and preferable curing characteristics,and the depth sensitivity of the modified powder slurries with 45 vol%solid loading increased by approximately 72%.Green scaffolds were subsequently printed from the slurries with a solid loading reaching 45 vol%via DLP 3D printing.The scaffolds had macropores(pore diameters of approximately 1 mm)and internal open micropores(pore diameters of approximately 5.7-13.0μm)after sintering.Additionally,these small-featured(approximately 320μm)scaffolds retained sufficient compressive strength((70.01±3.53)MPa)even with high porosity(approximately 73.95%).This work can facilitate the fabrication of multiscale porous metal scaffolds with high solid loading slurries,offering potential for applications requiring high specific surface area ratios.
基金supported by National Key R&D Program of China(No.2022YFE0138500)the Jilin Provincial Education Department Science Research Project(No.JJKH20231225KJ).
文摘The esophagus is an important part of the human digestive system.Due to its limited regenerative capacity and the infeasibility of donor transplantation,esophageal replacement has become an important problem to be solved urgently in clinics.In recent years,with the rapid development of tissue engineering technology in the biomedical field,tissue engineering stent(artificial esophagus)provides a new therapeutic approach for the repair and reconstruction of esophageal defects and has made remarkable progress.Biomedical esophageal stent materials have also experienced the development process from non-absorbable materials to absorbable materials,and then to new materials with composite cells and biological factors.In this paper,the composition,functional characteristics,and limitations of non-degradable scaffolds,biodegradable scaffolds,and Decellularized Matrix(DM)scaffolds specially designed for these applications are reviewed.Non-absorbable stents are typically composed of synthetic polymers or metals that provide structural support but fail to bind to surrounding tissues over time.In contrast,biodegradable stents are designed to break down gradually in the body while promoting cell infiltration and promoting new tissue formation.DM scaffolds can alleviate autoimmune reactions,preserve natural tissue characteristics,and enable recellularization during auto-repair.In addition,the significance of various cell-loaded materials in esophageal replacement has been explored,and the inclusion of cells in scaffold design has been shown to have the potential to enhance integration with host tissue and improve postoperative functional outcomes.These advances underscore ongoing efforts to closely mimic the structure of the natural esophagus.
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.
基金Project (51275179) supported by the National Natural Science Foundation of ChinaProject (2010A090200072) supported by Industry,University and Research Institute Combination of Ministry of Education, Ministry of Science and Technology and Guangdong Province,China+1 种基金Project (2012M511797) supported by China Postdoctoral Science FoundationProject (2012ZB0014) supported by FundamentalResearch Funds for the Central Universities of China
文摘The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.
基金supported by the National Key Research and Development Program of China(2019YFA0905200).
文摘The treatment of prolonged inflammation and cartilage damage due to osteoarthritis(OA)is a major clinical challenge.We developed a comprehensive cartilage repair therapy using a dual drug-loaded nanocomposite hydrogel that leveraged the spatiotemporal immunomodulatory effects of a naturally degradable protein-based nanocomposite hydrogel.The hydrogel acted as a scaffold that created a favorable microenvironment for cartilage regeneration.The hydrogel recruited macrophages and human mesenchymal stem cells(hMSCs),which supported the growth and adhesion of osteoblasts,and degraded to provide nutrition.Silk protein nanoparticles were chemically cross-linked with kartogenin,and humanlike collagen was physically cross-linked with dexamethasone through hydrogen bonding.In the early stages of cartilage repair,a large quantity of dexamethasone was released.The dexamethasone acted as an anti-inflammatory agent and a spatiotemporal modulator of the polarization of M1 macrophages into M2 macrophages.In the middle and late stages of cartilage repair,kartogenin underwent sustained release from the hydrogel,inducing the differentiation of hMSCs into chondrocytes and maintaining chondrocyte stability.Therefore,kartogenin and dexamethasone acted synergistically to induce cartilage repair.In conclusion,we developed an integrated therapeutic system by constructing a cartilage regeneration microenvironment and inducing synergistic drug-based cartilage regeneration.The therapeutic system demonstrated satisfactory efficacy for repairing cartilage damage in rabbits.
基金supported by the following funds:The National Natural Science Foundation of China(Nos.52275393,51935014,and 82072084)Jiangxi Provincial Natural Science Foundation of China(No.20224ACB204013)+2 种基金The Project of State Key Laboratory of Precision Manufacturing for Extreme Service Performancethe National Key Research and Development Program of China(No.2023YFB4605800)the Independent Exploration and Innovation Project of Central South University(No.1053320221707).
文摘Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser sintering.The results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in vitro.Antibacterial experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus aureus.Finally,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.
基金supported by National Natural Science Foundation of China,China(Grant ID:52475298)National Key Research and Development Program of China,China(Grant ID:2022YFB4600203)+3 种基金Young Elite Scientists Sponsorship Program by Jilin Association for Science and Technology,China(Grant ID:QT202323)Changchun Science and Technology Bureau(Grant ID:23YQ13)Department of Science and Technology of Jilin Province,China(Grant ID:20230402063GH)the 10th CAST Young Elite Scientists Sponsorship Program.
文摘In bone tissue engineering,scaffold design must achieve specific mechanical compatibility with implantation sites,critically determining implant performance.This study developed four cylindrical Ti6Al4V bone scaffolds via selective laser melting(SLM),incorporating distinct lattice architectures:Face-Centered Cubic(FCC),Body-Centered Cubic(BCC),Glass Sponge(GS),and Auxetic Structures(AS).Integrated experimental characterization and finite element simulations revealed exceptional mechanical superiority of FCC scaffolds,demonstrating 7-fold greater maximum stress compared to BCC,GS,and AS counterparts.Furthermore,FCC scaffolds exhibited optimal performance metrics including plateau stress(1.2-1.4 GPa),densification strain(0.15-0.25),energy absorption(85-100 MJ/m^(3)),and specific energy absorption(45-55 kJ/kg).These findings confirm that the unique energy dissipation mechanisms inherent to FCC lattice geometry significantly enhance energy absorption efficiency.The study provides a theoretical foundation for developing mechanically adaptive bone implants,particularly advancing clinical applications requiring enhanced energy absorption capabilities.
基金the Basic and Applied Basic Research Foundation of Guangdong Province,China(2022A1515140123)the Jiangsu Province Graduate Research and Practice Innovation Program(SJCX24_2504).
文摘Although Ti scaffolds offer great potential in orthopedic applications,their porous nature raises new questions,such as low relative density and high surface area.This work investigated the gradual decrease in the strength of Ti scaffolds during longterm immersion in Hank’s solution.After 180-day immersion,the samples have a 23.3% and 26.6% reduction in yield strength and a 9.0% and 11.2% reduction in compressive strength in dynamic and static solutions,indicating potential failure during the long-term service.A large exposure area to the solution leads to a high corrosion rate,which results in the consumption of the scaffolds and,consequently,decreased strength.Although the covered deposits on the scaffolds reduce the ion release to some extent,the scaffolds still have a slowly ongoing decrease in strength.Based on the durability considerations,some methods,such as decreasing porosity and surface treatments,are proposed to alleviate this phenomenon of Ti scaffolds.
文摘Scaffolds that emulate the architecture of human bone,combined with strong mechanical stability and biocompatibility,are vital for promoting effective bone tissue regeneration.However,most existing bone-mimetic scaffolds fall short in reproducing the intricate hierarchical structure of human bone,which restricts their practical application.This study introduces a novel strategy that combines rotational three-dimensional(3D)printing technology and sponge replication technique to fabricate bone-mimetic scaffolds based on composite materials comprising copper-substituted diopside and biphasic calcium phosphate.The scaffolds closely mimic the structure of human bone,featuring both cancellous and cortical bone with Haversian canals.Additionally,the scaffolds exhibit high porosity and transport capacity,while exhibiting compressive strength that is on par with human bone under both axial and lateral loads.Moreover,they demonstrate good biocompatibility and the potential to induce and support osteogenesis and angiogenesis.The scaffolds produced here present a pathway to remediating particularly large bone defects.Given their close resemblance to human bone structure and function,these scaffolds may be well-suited for developing in vitro bone disease models for pharmaceutical testing and various biomedical applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2022R1A4A1028747 and RS-2024-00344151).
文摘Recent advances in bone regeneration have introduced the concept of four-dimensional(4D)scaffolds that can undergo morphological and functional changes in response to external stimuli.While several studies have proposed patient-specific designs for defect sites,they often fail to adequately distinguish the advantages of 4D scaffolds over conventional 3D counterparts.This study aimed to investigate the potential benefits of 4D scaffolds in clinically challenging scenarios involving curved defects,where fixation is difficult.We proposed the use of Shape-Memory Polymers(SMPs)as a solution to address critical issues in personalized scaffold fabrication,including dimensional accuracy,measurement error,and manufacturing imprecision.Experimental results demonstrated that the Curved-Layer Fused Deposition Modeling(CLFDM)scaffold,which offers superior conformability to curved defects,achieved significantly higher interfacial contact with the defect area compared to traditional Fused Deposition Modeling(FDM)scaffolds.Specifically,the CLFDM scaffold facilitated bone regeneration of 25.59±4.72 mm^(3),which is more than twice the 9.37±1.36 mm^(3)observed with the 3D FDM scaffold.Furthermore,the 4D CLFDM scaffold achieved 75.38±11.65 mm^(3)of new bone formation after four weeks,approximately three times greater than that of the 3D CLFDM scaffold,regardless of surface micro-roughness.These results underscore that improved geometrical conformity between the scaffold and the defect site enhances cellular infiltration and contributes to more effective bone regeneration.The findings also highlight the promise of 4D scaffolds as a compelling strategy to overcome geometric and dimensional mismatches in the design of patient-specific scaffolds.
基金National Natural Science Foundation Council of China(Grant No.52305359)Hubei Provincial Natural Science Foundation of China(Grant No.2023AFB141)National Medical Products Administration Key Laboratory for Dental Materials(PKUSS20240401)。
文摘In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.
基金supported by the National Natural Science Foundation of China(No.52175278).
文摘Articular cartilage,which plays a vital role in joint structure,is susceptible to damage from trauma and degenerative joint diseases.Traditional methods for cartilage treatment often involve complex surgical procedures with limited efficacy.Alternatively,implantable drug-loaded scaffolds are an increasingly attractive cartilage treatment option.To address the challenges of structural and functional compatibility between scaffolds and native cartilage,as well as issues related to drug loading,we design a novel cartilage scaffold with a four-region hollow porous fiber network structure.Using an extrusion-based 3D printing platform,a biphasic silicone ink composed primarily of liquid-phase silicone and solid particles was employed to construct the hollow porous fiber network.Mechanical compression tests demonstrate that the cartilage scaffold has mechanical characteristics similar to those of native cartilage tissue,and ultraviolet spectrophotometry measurements confirm its ability to control drug release.These results showcase the feasibility and effectiveness of the proposed cartilage substitute structure.
基金supported by the National Natural Science Foundation of China(Nos.52235008 and U2341270)the National Natural Science Foundation of China(No.52105341)。
文摘Poly-ether-ether-ketone/nano-silicon nitride(PEEK/nSN)composite scaffolds,fabricated by laser powder bed fusion(LPBF),show great potential for orthopedic applications due to their excellent biological performance and mechanical adaptability.However,the effect of nSN on LPBF processability and scaffold properties remains unclear.This study systematically investigates the processability and mechanical per-formance of PEEK/nSN composites to enable reliable clinical fabrication.The results show that adding nSN improves powder flowability and inhibits crystallization,enhancing LPBF processability.The introduction of nSN reduces PEEK’s non-isothermal crystallization Avrami exponent from 3.04 to 2.01,suggesting a transformation from a three-dimensional spherulitic to a two-dimensional lamellar crystal structure.Tensile tests reveal that the presence of nSN alters the optimal process parameters,reducing the optimal laser power from 25 W to 22 W due to increased energy absorption efficiency,as shown by an increase in absorbance at 843 cm^(-1)from 0.27 to 0.35 as the nSN content increases to 2 wt%.Porous diamond-structured scaffolds were fabricated using optimal parameters for pure PEEK,PEEK/1 wt%nSN,and PEEK/2 wt%nSN.Diamond-structured scaffolds fabricated with 1 wt%nSN showed a 12.2%increase in elastic modulus compared to pure PEEK,highlighting the enhanced mechanical performance.Over-all,this study offers key insights into the stable and customizable LPBF fabrication of PEEK/nSN porous scaffolds,providing a foundation for future research on their bioactivity and antibacterial properties for orthopedic applications.
