The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step...The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.展开更多
In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this stu...In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.展开更多
Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties o...Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties of biomaterials.These underlying mechanisms and pathways provide inspiration for the design and construction of materials for repairing hard tissues.Due to good biocompatibility of hydrogels,materials using gel-like systems as media are inextricably linked to biological macrocomponents and mineralization.Inspired by those bioprocesses,polyacrylamide hydrogel with enzymes was 3D printed to form controlled shapes and structures,then was used as templates for mineralization.Effect of polyacrylamide hydrogel pore size on the mineralization was studied via incorporating NaF and CaCl2 and controlling the mineralization degree.The mineralization processes of 3D printed hydrogels with different pore sizes were also explored to find out the confinement influence of pores.Mineralization in hydrogels with smaller pores is developed in a columnar stacked pattern,which is similar to the vesicular mineralization stage of bone mineralization.展开更多
3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have...3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.展开更多
The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach...The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.展开更多
Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have ...Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have limited sensitivity and poor stability due to their bulk structure and strain concentration during stretching.In this study,we designed and fabricated diamond-,grid-,and peanut-shaped organohydrogel based on positive,near-zero,and negative Poisson’s ratios using digital light processing(DLP)-based 3D printing technology.Through structural design and optimization,the grid-shaped organohydrogel exhibited record sensitivity with gauge factors of 4.5(0–200%strain,ionic mode)and 13.5/1.5×10^(6)(0-2%/2%-100%strain,electronic mode),alongside full resistance recovery for enhanced stability.The 3D-printed grid structure enabled direct wearability and breathability,overcoming traditional sensor limitations.Integrated with a robotic hand system,this sensor demonstrated clinical potential through precise monitoring of paralyzed patients’grasping movements(with a minimum monitoring angle of 5°).This structural design paradigm advanced flexible electronics by synergizing high sensitivity,stability,wearability,and breathability for healthcare,and human-machine interfaces.展开更多
Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerg...Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues.In this study,coiled poly(ε-caprolactone)(PCL)fibrous bundles were fabricated using an alginate-based composite system,and processed with 3D printing.The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut,thereby transforming aligned PCL fibers into coiled structures.The effects of printing parameters,such as pneumatic pressure and nozzle moving speed,on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers.The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells(hASCs),supporting its potential in bone tissue engineering.展开更多
The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of...The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of Three-Dimensional(3D)-printed Polycaprolactone(PCL)scaffolds with varying proportions of Nanohydroxyapatite(NHA)and Nanoclay(NC),and their physiochemical and biological properties were assessed.The mechanical properties of PCL are satisfactory;however,its hydrophobic nature and long-term degradation hinder its use in scaffold fabrication.NHA and NC have been employed to improve the hydrophilic characteristics,mechanical strength,adhesive properties,biocompatibility,biodegradability,and osteoconductive behavior of PCL.The morphology results demonstrated 3D-printed structures with interconnected rectangular macropores and proper nanoparticle distribution.The sample containing 70 wt%NC showed the highest porosity(65.98±2.54%),leading to an increased degradation rate.The compressive strength ranged from 10.65±1.90 to 84.93±9.93 MPa,which is directly proportional to the compressive strength of cancellous bone(2–12 MPa).The wettability,water uptake,and biodegradability of PCL scaffolds considerably improved as the amount of NC increased.The results of the cellular assays exhibited increased proliferation,viability,and adhesion of MG-63 cells due to the addition of NHA and NC to the scaffolds.Finally,according to the in vitro results,it can be concluded that 3D-printed samples with higher amounts of NC can be regarded as a suitable scaffold for expediting the regeneration process of bone defects.展开更多
Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This pape...Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This paper draws inspiration from the Quasi-Zero Stiffness (QZS) characteristics resulting from the buckling deformation of beams, and proposes a gear-based QZS structure by arranging beams in a circular array. We investigated the static mechanical behavior under different structural parameters, loading angles, and gear combinations through experiments and simulations, and demonstrated the mechanical performances could be effectively programmed. Subsequent vibration isolation tests on the double gears prove superior vibration isolation performance at low frequency while maintaining high load-bearing capacities. Additionally, a key contribution of our work is the development of a mathematical model to characterize the buckling behavior of the unit beam within the gear structure, with its accuracy validated through finite element analysis and experimental results. The gear’s modulus, number of teeth, and pressure angle are selected according to standard series, allowing the gear can be seamlessly integrated into existing mechanical systems in critical fields such as aerospace, military, and etc.展开更多
The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor...The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.展开更多
Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early in...Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early intervention and combination therapy tailored to the individual needs of the patients are crucial for achieving optimal results.Three-dimensional(3D)printing technology,a rapid prototyping technique,is increasingly being applied in the medical field.The customization and precise functionality of 3D printing technology are particularly important for the rehabilitation of HS.This review provides an overview of HS and the role of 3D printing technology in medical applications,analyses the application of 3D-printed rehabilitation aids for HS,and discusses the use of 3D printing technology to improve HS treatment outcomes,thereby providing clinical guidance for effective HS rehabilitation.展开更多
Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiot...Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiotics are usually used to treat H.pylori infections,whereas traditional quadruple therapy has side effects including headaches,nausea,diarrhea,intestinal dysbacteriosis,antibiotic resistance,and repeat infections.Here,a drug-loaded magnetic microbullet was designed to realize long-term retention in the stomach for one-shot treatment for H.pylori infections.It comprises a hollow cylinder wherein eight microneedles homogenously distribute at the top and several round pores located at the bottom.Itwas three-dimensional(3D)-printed by stereolithography.A clarithromycin(CAM)ground mixture(CGM)was prepared to improve solubility.Enough CGM powders were filled into the cylinder,covered by a small round magnet,and sealed to form a CAM-loaded magnetic microbullet(CMMB).CAM continually released from CMMBs for>24 h.With outside magnetic guidance,an oral CMMB targeted the pylorus site and the microneedles immediately headed into the mucosa followed by long-term local drug release.The in vitro and in vivo safety of CMMBs was confirmed,where their swelling rates were low,and the oral CMMB was finally completely evacuated.An oral CMMB was administered to H.pylori-infected mice and maintained in the stomach for 36 h with magnetic guidance,and the successful eradication of H.pylori was confirmed after single-dose administration.Oral CMMBs are a convenient medication for the eradication of H.pylori.展开更多
In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati...In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.展开更多
The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actu...The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actuators,sensors,and robotic systems that require safe interaction and precise manipulation.Unlike traditional techniques,3D printing offers enhanced capabilities in tailoring structural complexity,resolution,and integrated functionality,enabling the direct fabrication of hydrogel systems with programmed mechanical and functional properties.In this perspective,we explore the evolving role of 3D-printed hydrogels in soft robotics,covering their material composition,fabrication techniques,and diverse applications.We highlight advancements in hydrogel-based actuators,sensors,and robots,emphasizing their ability to perform intricate motions.In addition,we discuss challenges like mechanical robustness,scalability,and integration as well as the potential of hydrogels in soft robotics and explore future directions for their development.展开更多
4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response ...4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response to external stimuli such as temperature,magnetic fields,and light.Among the most popular types of 4D-printed structures are thermally responsive bilayer actuators using shape memory polymers,valued for their programmability and convenience.However,achieving precise deformations without collisions is hindered by the nonlinear and time-varying morphing process of these bilayer actuators,which is crucial for creating dynamically controllable shapes on demand in 4D printing.This study presents a rapid and effective design and optimization strategy for 4D printed self-folding structures that can be sequentially and accurately folded.Theoretical analyses were conducted to guide the design of the folding processes.The response surface method(RSM)was used to investigate key parameters affecting the design of 4D-printed bilayer actuators.The results indicate that increasing printing speed enhances internal strain,whereas higher printing temperatures,layer heights,or actuator heights have the opposite effect.The RSM model achieved an R-squared value of 0.983,accurately capturing the coupling effects of these variables on the output responses,thereby enabling controlled timescales for bending motion and sequential folding without collisions.These findings can be applied to enhance the design and acceleration of 4D-printed self-folding structures,ensuring controlled speed of shape transformation.To validate this concept,a self-folding hand-shaped structure with five fingers was designed and fabricated,demonstrating how design and printing parameters can precisely control the timescale of shape changes for each finger based on the design specifications.展开更多
Additive manufacturing(AM),a key technology in the evolution of Industry 4.0,has revolutionized production processes by enabling the precise,layer-by-layer fabrication of complex and customized components,enhancing ef...Additive manufacturing(AM),a key technology in the evolution of Industry 4.0,has revolutionized production processes by enabling the precise,layer-by-layer fabrication of complex and customized components,enhancing efficiency and flexibility in smart manufacturing systems.However,one significant challenge hindering the acceptance of this technology is the limited print size,constrained by the machine’s small bed.To address this issue,a suitable polymer joining technique could be applied as a post-fabrication step.The present article examines findings on the Ultrasonic Welding(UW)of Material Extrusion(MEX)-3D printed parts made from commonly used thermoplastics,Acrylonitrile Butadiene Styrene(ABS)and Polylactic Acid(PLA).Key parameters in the process are identified and optimized through statistical methods,such as Design of Experiments(DOE),Taguchi,and Analysis of Variance(ANOVA).The findings showed that the material combination and the design of the energy directors had the greatest impact on the joint strength and elongation,leading to a joint efficiency increase of up to 174.52%.The research’s feasibility was additionally supported by applying the results to weld and fabricate a car’s rear wing and an agricultural drone,both of which demonstrated strong structural integrity.The proposed method is anticipated to increase acceptance of joining and welding techniques in the future,with UW showing significant potential for effectively joining 3D-printed parts and addressing the bed size limitations of 3D printers.展开更多
The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires exp...The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires experienced doctors and lim-its the sharing and discussion of therapeutic plans[1].展开更多
3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of t...3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of these materials,primarily influenced by the dynamic fiber pullout interface strength necessitates investigation into the rate-dependent fiber/matrix interfacial strength.This study modifies a Hopkinson tension bar to conduct dynamic pullout tests on a single fiber bundle,utilizing a low-impedance bar and an in-situ calibrated semiconductor strain gauge to capture weak stress signals.Stress equilibrium analyses are performed to validate the transient dynamic loading on single fiber bundle specimens.The results reveal that the fiber/matrix interfacial strength is rate-dependent,increasing with the loading rate,while remaining unaffected by the embedded length.Fracture microstructural analyses show minimal fiber pullout due to high interfacial stresses induced by longer embedded lengths.Lastly,suggestions are made for the efficient design of fiber pullout experiments.展开更多
Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structure...Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structures have attracted attention owing to their distinctive configurations and promising applications in biomimetics and microelectronics.However,the helical deformation behavior of fiber actuators is critically influenced by their morphologies and alignments;yet,the underlying mechanisms are not fully understood.Through a two-step azaMichael addition reaction and direct ink writing(DIW)4D printing technology,fiber-based LCE actuators with a core-sheath alignment structure were fabricated and exhibited reversible helical deformation upon heating.By adjusting the printing parameters,the filament number,width,thickness,and core-sheath structure of the fiber actuators can be precisely controlled,resulting in deformation behaviors,such as contraction,bending,and helical twisting.Finite element simulations were performed to investigate the deformation behaviors of the fiber actuators,providing insights into the variations in stress and strain during the shape-changing process,which can be used to explain the shape-morphing mechanism.These findings demonstrate that the precise tuning of printing parameters enables the controllable construction of LCE actuator morphology and customization of their functional properties,paving the way for advanced applications in smart fabrics,biomedical engineering,and flexible electronics.展开更多
Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylened...Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)is widely used in FECDs due to its excellent mechanical flexibility,tunable conductivity,and non-toxicity.However,the manufacturing process for patterned PEDOT:PSS electrochromic devices remains intricate,costly,and challenging to personalize.To address this challenge,we have developed a 3D-printable ink with controllable rheological properties through a concentration-tuning strategy,enabling programmable,patterned printing of PEDOT-based conductive polymer electrochromic layers.The 3D-printed FECDs exhibit outstanding electrochromic performance,including a high optical contrast(up to 47.9%at 635 nm),fast response times(t_(c)=1.6 s;t_(b)=0.6 s),high coloration efficiency(352 cm^(2) C^(-1)),and good cycling stability(with only a 9.3%decrease in optical contrast after 100 electrochemical cycles).Finally,we utilize 3D printing technology to construct flexible,patterned PEDOT:PSS electrochromic devices with bespoke butterfly designs.This work establishes the theoretical foundation for the application of 3D printing technology in PEDOT:PSS flexible electrochromic devices.展开更多
基金supported by the National Natural Science Foundation of China(No.U21A2055),Natural Science Foundation of Tianjin of China(No.21JCQNJC01280)Tianjin Key R&D Program Beijing-Tianjin-Hebei Collaborative Innovation Project(No.22YFXTHZ00120).
文摘The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.
文摘In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.
基金Funded by the Joint Fund of Natural Science Foundation of Hubei Province(No.2024AFD033)the Open Fund of Hubei Longzhong Laboratory。
文摘Biomineralization of natural composites are usually highly finely adjusted to achieve extremely precise control over the shape,size and distribution of inorganic crystals,giving them unique structures and properties of biomaterials.These underlying mechanisms and pathways provide inspiration for the design and construction of materials for repairing hard tissues.Due to good biocompatibility of hydrogels,materials using gel-like systems as media are inextricably linked to biological macrocomponents and mineralization.Inspired by those bioprocesses,polyacrylamide hydrogel with enzymes was 3D printed to form controlled shapes and structures,then was used as templates for mineralization.Effect of polyacrylamide hydrogel pore size on the mineralization was studied via incorporating NaF and CaCl2 and controlling the mineralization degree.The mineralization processes of 3D printed hydrogels with different pore sizes were also explored to find out the confinement influence of pores.Mineralization in hydrogels with smaller pores is developed in a columnar stacked pattern,which is similar to the vesicular mineralization stage of bone mineralization.
基金funded by the National Natural Science Foundation of China(Grant No.06101213)the National Natural Science Foundation of China(Grant No.22105160).
文摘3D printing technology enhances the combustion characteristics of hybrid rocket fuels by enabling complex geometries. However, improvements in regression rates and energy properties of monotonous 3D printed fuels have been limited. This study explores the impact of poly(vinylidene fluoride) and polydopamine-coated aluminum particles on the thermal and combustion properties of 3D printed hybrid rocket fuels. Physical self-assembly and anti-solvent methods were employed for constructing composite μAl particles. Characterization using SEM, XRD, XPS, FTIR, and μCT revealed a core-shell structure and homogeneous elemental distribution. Thermal analysis showed that PVDF coatings significantly increased the heat of combustion for aluminum particles, with maximum enhancement observed in μAl@PDA@PVDF(denoted as μAl@PF) at 6.20 k J/g. Subsequently, 3D printed fuels with varying pure and composite μAl particle contents were prepared using 3D printing. Combustion tests indicated higher regression rates for Al@PF/Resin composites compared to pure resin, positively correlating with particle content. The fluorocarbon-alumina reaction during the combustion stage intensified Al particle combustion, reducing residue size. A comprehensive model based on experiments provides insights into the combustion process of PDA and PVDF-coated droplets. This study advances the design of 3D-printed hybrid rocket fuels, offering strategies to improve regression rates and energy release, crucial for enhancing solid fuel performance for hybrid propulsion.
基金Open access funding provided by Ben-Gurion University.
文摘The SafeAmpCase is an innovative 3D-printed solution developed to address critical challenges in transporting and storing fragile glass drug ampoules during emergencies.This study employs a multidisciplinary approach—integrating biomedical engineering,advanced materials science,and emergency medicine expertise—to develop a compact,durable,and user-friendly ampoule case.A key innovation lies in the strategic selection of thermoplastic polyurethane(TPU)as the material,leveraging its superior impact resistance,flexibility,and noise-damping characteristics to ensure reliability under performance in demanding real-world conditions.To optimize the 3D printing process,key parameters,including printing temperature(220-250℃),volumetric flow rate(3-20 mm^(3)/s),retraction speed(30-90 mm/s),and retraction length(0.4-1.2 mm),were systematically adjusted using calibration models.The final optimized parameters(245℃,7 mm^(3)/s,90 mm/s,and 1.2 mm)reduced production time by 43%while preserving structural integrity.American Society for Testing and Materials(ASTM)international standard drop tests confirmed the case’s exceptional impact resistance,demonstrating a 90%reduction in ampoule breakage compared to polylactic acid plus.Further refinements,guided by feedback from 25 emergency professionals,resulted in medicationspecific color coding and an enhanced locking mechanism for usability in high-pressure situations.The final SafeAmpCase model withstood 18 consecutive drop trials without ampoule breakage,confirming its robustness in field conditions.This research underscores the transformative potential of additive manufacturing in developing customized,high-performance solutions for critical healthcare applications,setting a new benchmark for biomedical device design and rapid prototyping.
基金financially supported by the National Key R&D Program of China (2022YFE0197100, 2023YFB4603500)Shenzhen Science and Technology Innovation Commission (KQTD20190929172505711)+1 种基金supported by MOE SUTD Kickstarter initiative (SKI2021_02_16)Singapore Ministry of Education academic research grant Tier 2 (MOE-T2EP50121-0007).
文摘Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility,stretchability,and skin-like compliance.However,these sensors often have limited sensitivity and poor stability due to their bulk structure and strain concentration during stretching.In this study,we designed and fabricated diamond-,grid-,and peanut-shaped organohydrogel based on positive,near-zero,and negative Poisson’s ratios using digital light processing(DLP)-based 3D printing technology.Through structural design and optimization,the grid-shaped organohydrogel exhibited record sensitivity with gauge factors of 4.5(0–200%strain,ionic mode)and 13.5/1.5×10^(6)(0-2%/2%-100%strain,electronic mode),alongside full resistance recovery for enhanced stability.The 3D-printed grid structure enabled direct wearability and breathability,overcoming traditional sensor limitations.Integrated with a robotic hand system,this sensor demonstrated clinical potential through precise monitoring of paralyzed patients’grasping movements(with a minimum monitoring angle of 5°).This structural design paradigm advanced flexible electronics by synergizing high sensitivity,stability,wearability,and breathability for healthcare,and human-machine interfaces.
基金supported by the‘Korea National Institute of Health’research project(2022ER130502)a grant from by SMC-SKKU Future Convergence Academic Research Program,2024supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2024-00336758)。
文摘Biomedical scaffold fabrication has seen advancements in mimicking the native extracellular matrix through intricate three-dimensional(3D)structures conducive to tissue regeneration.Coiled fibrous scaffolds have emerged as promising substrates owing to their ability to provide unique topographical cues.In this study,coiled poly(ε-caprolactone)(PCL)fibrous bundles were fabricated using an alginate-based composite system,and processed with 3D printing.The unique structure was obtained through the die-swell phenomenon related to the release of residual stresses from the printed strut,thereby transforming aligned PCL fibers into coiled structures.The effects of printing parameters,such as pneumatic pressure and nozzle moving speed,on fiber morphology were investigated to ensure a consistent formation of coiled PCL fibers.The resulting coiled PCL fibrous scaffold demonstrated higher activation of mechanotransduction signaling as well as upregulation of osteogenic-related genes in human adipose stem cells(hASCs),supporting its potential in bone tissue engineering.
文摘The field of bone tissue engineering has experienced an increase in prevalence due to the inherent challenge of the natural regeneration of significant bone deformities.This investigation focused on the preparation of Three-Dimensional(3D)-printed Polycaprolactone(PCL)scaffolds with varying proportions of Nanohydroxyapatite(NHA)and Nanoclay(NC),and their physiochemical and biological properties were assessed.The mechanical properties of PCL are satisfactory;however,its hydrophobic nature and long-term degradation hinder its use in scaffold fabrication.NHA and NC have been employed to improve the hydrophilic characteristics,mechanical strength,adhesive properties,biocompatibility,biodegradability,and osteoconductive behavior of PCL.The morphology results demonstrated 3D-printed structures with interconnected rectangular macropores and proper nanoparticle distribution.The sample containing 70 wt%NC showed the highest porosity(65.98±2.54%),leading to an increased degradation rate.The compressive strength ranged from 10.65±1.90 to 84.93±9.93 MPa,which is directly proportional to the compressive strength of cancellous bone(2–12 MPa).The wettability,water uptake,and biodegradability of PCL scaffolds considerably improved as the amount of NC increased.The results of the cellular assays exhibited increased proliferation,viability,and adhesion of MG-63 cells due to the addition of NHA and NC to the scaffolds.Finally,according to the in vitro results,it can be concluded that 3D-printed samples with higher amounts of NC can be regarded as a suitable scaffold for expediting the regeneration process of bone defects.
基金supported in part by National Key R&D Program of China under Grant 2024YFB4708600National Natural Science Foundation of China under Grant 52305304+3 种基金Jilin Youth Growth Technology Project under Grant 20230508147RCthe Science and Technology Research Project of Jilin Provincial Education Department(No.JJKH20231193KJ)supported in part by the National Natural Science Foundation of China under Grant 52021003 and Grant 52205565in part by the Natural Science Foundation of Jilin Province under Grant 20210101053JC.
文摘Traditional linear vibration isolators struggle to combine high load-bearing capacity with low-frequency vibration isolation, whereas nonlinear metastructure isolators can effectively fulfill both functions. This paper draws inspiration from the Quasi-Zero Stiffness (QZS) characteristics resulting from the buckling deformation of beams, and proposes a gear-based QZS structure by arranging beams in a circular array. We investigated the static mechanical behavior under different structural parameters, loading angles, and gear combinations through experiments and simulations, and demonstrated the mechanical performances could be effectively programmed. Subsequent vibration isolation tests on the double gears prove superior vibration isolation performance at low frequency while maintaining high load-bearing capacities. Additionally, a key contribution of our work is the development of a mathematical model to characterize the buckling behavior of the unit beam within the gear structure, with its accuracy validated through finite element analysis and experimental results. The gear’s modulus, number of teeth, and pressure angle are selected according to standard series, allowing the gear can be seamlessly integrated into existing mechanical systems in critical fields such as aerospace, military, and etc.
基金supported by National Natural Science Foundation of China(52072173)International Science and Technology cooperation program of Jiangsu Province(SBZ2022000084)Funding for Outstanding Doctoral Dissertation in NUAA(BCXJ23-10).
文摘The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.
基金supported by the Cross-Disciplinary Research Fund Project of the Shanghai Ninth People’s Hospital of Shanghai Jiao Tong University School of Medicine(grant no.JYJC202236)the Shanghai Plastic Surgery Research Center of Shanghai Priority Research Center(grant no.2023ZZ02023)the Shanghai Healthcare System Key Supporting Disciplines Program(grant no.2023ZDFC0303).
文摘Hypertrophic scars(HS)are fibrotic proliferative diseases that develop after deep skin injuries caused by trauma,burns,and surgery.Traditional treatment methods include both surgical and nonsurgical therapies.Early intervention and combination therapy tailored to the individual needs of the patients are crucial for achieving optimal results.Three-dimensional(3D)printing technology,a rapid prototyping technique,is increasingly being applied in the medical field.The customization and precise functionality of 3D printing technology are particularly important for the rehabilitation of HS.This review provides an overview of HS and the role of 3D printing technology in medical applications,analyses the application of 3D-printed rehabilitation aids for HS,and discusses the use of 3D printing technology to improve HS treatment outcomes,thereby providing clinical guidance for effective HS rehabilitation.
基金supported by the National Natural Science Foundation of China(82073791).
文摘Infections of Helicobacter pylori(H.pylori)affect 42.1%of Chinese and 43.1%of the world population.H.pylori inhabits the mucous sublayer at the pylorus,leading to gastric ulcers,gastritis,and even cancer.Oral antibiotics are usually used to treat H.pylori infections,whereas traditional quadruple therapy has side effects including headaches,nausea,diarrhea,intestinal dysbacteriosis,antibiotic resistance,and repeat infections.Here,a drug-loaded magnetic microbullet was designed to realize long-term retention in the stomach for one-shot treatment for H.pylori infections.It comprises a hollow cylinder wherein eight microneedles homogenously distribute at the top and several round pores located at the bottom.Itwas three-dimensional(3D)-printed by stereolithography.A clarithromycin(CAM)ground mixture(CGM)was prepared to improve solubility.Enough CGM powders were filled into the cylinder,covered by a small round magnet,and sealed to form a CAM-loaded magnetic microbullet(CMMB).CAM continually released from CMMBs for>24 h.With outside magnetic guidance,an oral CMMB targeted the pylorus site and the microneedles immediately headed into the mucosa followed by long-term local drug release.The in vitro and in vivo safety of CMMBs was confirmed,where their swelling rates were low,and the oral CMMB was finally completely evacuated.An oral CMMB was administered to H.pylori-infected mice and maintained in the stomach for 36 h with magnetic guidance,and the successful eradication of H.pylori was confirmed after single-dose administration.Oral CMMBs are a convenient medication for the eradication of H.pylori.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.
基金supported by Singapore MOE Tier-2 Award MOE-T2EP50123-0015.
文摘The integration of 3D-printed hydrogels in soft robotics enables the creation of flexible,adaptable,and biocompatible systems.Hydrogels,with their high-water content and responsiveness to stimuli,are suitable for actuators,sensors,and robotic systems that require safe interaction and precise manipulation.Unlike traditional techniques,3D printing offers enhanced capabilities in tailoring structural complexity,resolution,and integrated functionality,enabling the direct fabrication of hydrogel systems with programmed mechanical and functional properties.In this perspective,we explore the evolving role of 3D-printed hydrogels in soft robotics,covering their material composition,fabrication techniques,and diverse applications.We highlight advancements in hydrogel-based actuators,sensors,and robots,emphasizing their ability to perform intricate motions.In addition,we discuss challenges like mechanical robustness,scalability,and integration as well as the potential of hydrogels in soft robotics and explore future directions for their development.
基金supported by National Natural Science Foundation of China(Grant No.52375272)Zhejiang Provincial Natural Science Foundation of China(Grant No.LR22E050006)China Postdoctoral Science Foundation(Grant Nos.2024M751644,2024M754069).
文摘4D printing technology represents a new generation of additive manufacturing methods that enable three-dimensional(3D)printed structures to change their shapes or properties over time(the fourth dimension)in response to external stimuli such as temperature,magnetic fields,and light.Among the most popular types of 4D-printed structures are thermally responsive bilayer actuators using shape memory polymers,valued for their programmability and convenience.However,achieving precise deformations without collisions is hindered by the nonlinear and time-varying morphing process of these bilayer actuators,which is crucial for creating dynamically controllable shapes on demand in 4D printing.This study presents a rapid and effective design and optimization strategy for 4D printed self-folding structures that can be sequentially and accurately folded.Theoretical analyses were conducted to guide the design of the folding processes.The response surface method(RSM)was used to investigate key parameters affecting the design of 4D-printed bilayer actuators.The results indicate that increasing printing speed enhances internal strain,whereas higher printing temperatures,layer heights,or actuator heights have the opposite effect.The RSM model achieved an R-squared value of 0.983,accurately capturing the coupling effects of these variables on the output responses,thereby enabling controlled timescales for bending motion and sequential folding without collisions.These findings can be applied to enhance the design and acceleration of 4D-printed self-folding structures,ensuring controlled speed of shape transformation.To validate this concept,a self-folding hand-shaped structure with five fingers was designed and fabricated,demonstrating how design and printing parameters can precisely control the timescale of shape changes for each finger based on the design specifications.
文摘Additive manufacturing(AM),a key technology in the evolution of Industry 4.0,has revolutionized production processes by enabling the precise,layer-by-layer fabrication of complex and customized components,enhancing efficiency and flexibility in smart manufacturing systems.However,one significant challenge hindering the acceptance of this technology is the limited print size,constrained by the machine’s small bed.To address this issue,a suitable polymer joining technique could be applied as a post-fabrication step.The present article examines findings on the Ultrasonic Welding(UW)of Material Extrusion(MEX)-3D printed parts made from commonly used thermoplastics,Acrylonitrile Butadiene Styrene(ABS)and Polylactic Acid(PLA).Key parameters in the process are identified and optimized through statistical methods,such as Design of Experiments(DOE),Taguchi,and Analysis of Variance(ANOVA).The findings showed that the material combination and the design of the energy directors had the greatest impact on the joint strength and elongation,leading to a joint efficiency increase of up to 174.52%.The research’s feasibility was additionally supported by applying the results to weld and fabricate a car’s rear wing and an agricultural drone,both of which demonstrated strong structural integrity.The proposed method is anticipated to increase acceptance of joining and welding techniques in the future,with UW showing significant potential for effectively joining 3D-printed parts and addressing the bed size limitations of 3D printers.
基金supported by grants from Jilin Scientific and Technological Development Program(20200403090SF)The Health Special Foundation of Jilin Province of China(2020sczt029).
文摘The anatomy of the human liver is complex,and the vascular system is highly variable.Moreover,the use of traditional com-puted tomography(CT)two-dimensional(2D)images to recon-struct the tissue and organs requires experienced doctors and lim-its the sharing and discussion of therapeutic plans[1].
基金supported by the Key Research and Development Plan of Shaanxi Province(No.2023-GHZD-12)the Chinese Aeronautical Establishment Aeronautical Science Foundation(No.20230041053006)the National Natural Science Foundation of China(Nos.12472392 and 12172304).
文摘3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of these materials,primarily influenced by the dynamic fiber pullout interface strength necessitates investigation into the rate-dependent fiber/matrix interfacial strength.This study modifies a Hopkinson tension bar to conduct dynamic pullout tests on a single fiber bundle,utilizing a low-impedance bar and an in-situ calibrated semiconductor strain gauge to capture weak stress signals.Stress equilibrium analyses are performed to validate the transient dynamic loading on single fiber bundle specimens.The results reveal that the fiber/matrix interfacial strength is rate-dependent,increasing with the loading rate,while remaining unaffected by the embedded length.Fracture microstructural analyses show minimal fiber pullout due to high interfacial stresses induced by longer embedded lengths.Lastly,suggestions are made for the efficient design of fiber pullout experiments.
基金financially supported by the National Natural Science Foundation of China(Nos.52103145 and 11832007)Science&Technology Department of Sichuan Province(No.2025ZNSFSC0352)State Key Laboratory of Polymer Materials Engineering(No.sklpme-2024-1-03)。
文摘Liquid crystal elastomers(LCEs)exhibit exceptional reversible deformation and unique physical properties owing to their order-disorder phase transition under external stimuli.Among these deformations,helical structures have attracted attention owing to their distinctive configurations and promising applications in biomimetics and microelectronics.However,the helical deformation behavior of fiber actuators is critically influenced by their morphologies and alignments;yet,the underlying mechanisms are not fully understood.Through a two-step azaMichael addition reaction and direct ink writing(DIW)4D printing technology,fiber-based LCE actuators with a core-sheath alignment structure were fabricated and exhibited reversible helical deformation upon heating.By adjusting the printing parameters,the filament number,width,thickness,and core-sheath structure of the fiber actuators can be precisely controlled,resulting in deformation behaviors,such as contraction,bending,and helical twisting.Finite element simulations were performed to investigate the deformation behaviors of the fiber actuators,providing insights into the variations in stress and strain during the shape-changing process,which can be used to explain the shape-morphing mechanism.These findings demonstrate that the precise tuning of printing parameters enables the controllable construction of LCE actuator morphology and customization of their functional properties,paving the way for advanced applications in smart fabrics,biomedical engineering,and flexible electronics.
基金supported by the Natural Science Foundation of Jiangxi Province(20232ACB204002&20232BAB202044)Jiangxi Provincial Key Laboratory of Flexible Electronics(20212BCD42004&20242BCC32010).
文摘Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)is widely used in FECDs due to its excellent mechanical flexibility,tunable conductivity,and non-toxicity.However,the manufacturing process for patterned PEDOT:PSS electrochromic devices remains intricate,costly,and challenging to personalize.To address this challenge,we have developed a 3D-printable ink with controllable rheological properties through a concentration-tuning strategy,enabling programmable,patterned printing of PEDOT-based conductive polymer electrochromic layers.The 3D-printed FECDs exhibit outstanding electrochromic performance,including a high optical contrast(up to 47.9%at 635 nm),fast response times(t_(c)=1.6 s;t_(b)=0.6 s),high coloration efficiency(352 cm^(2) C^(-1)),and good cycling stability(with only a 9.3%decrease in optical contrast after 100 electrochemical cycles).Finally,we utilize 3D printing technology to construct flexible,patterned PEDOT:PSS electrochromic devices with bespoke butterfly designs.This work establishes the theoretical foundation for the application of 3D printing technology in PEDOT:PSS flexible electrochromic devices.
