Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,w...Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,with their multifaceted and intricate designs,some robots often grapple with motion and functionality issues when confronted with tight spaces characterized by small cross-sectional dimensions.In this study,drawing inspiration from the high aspect ratio and undulating swimming patterns of snakes,a millimeter-scale,snake-like robot was designed and fabricated via a combination of extrusion-based four-dimensional(4D)printing and magnetic-responsive intelligent functional inks.A sophisticated motion control strategy was also developed,which enables the robots to perform various dynamic movements,such as undulating swimming,precise turns,graceful circular motions,and coordinated cluster movements,under diverse magnetic field variations.As a potential application,the snake robot can navigate and release drugs in a model coronary intervention vessel with tortuous channels and fluid filling.The novel design and promising applications of this snake robot are invaluable tools in future medical surgeries and interventions.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
“Life”represents a distinctive attribute inherent to organisms in nature,evident in their capacity to actively adapt to changes in their environment.In contrast to the static and intricate constructs of additive man...“Life”represents a distinctive attribute inherent to organisms in nature,evident in their capacity to actively adapt to changes in their environment.In contrast to the static and intricate constructs of additive manufacturing(AM),the dynamic structure of 4D printing(4DP)adeptly integrates AM technology,responsive mechanisms,and external stimuli,imbuing it with a semblance of“life.”This fusion significantly broadens its functional applica-tions across biomedicine,actuators,and metamaterials.The escalating demand across diverse fields necessitates heightened criteria for 4DP,encompassing rapid response,multi-stimulus response,large shape change,and specific mechanical properties(e.g.,high strength,high modulus)capable of accommodating varying environ-mental conditions.In recent years,shape memory polymers(SMPs)have garnered increasing attention among 4DP researchers due to their ease of design and preprogramming at the molecular level,facilitating controlled transformations along predictable pathways.However,4DP of high-strength SMPs,as an indispensable part of the high-performance field,is full of challenges because the intrinsic properties of the raw materials are not well compatible with the printing principle and the printed configuration is not flexible enough.Consequently,this paper provides a concise overview of the response mechanisms and applications of five prominent high-strength SMPs utilized in 4DP:epoxy resin,poly(ether-ether-ketone),polyimide,polylactic acid,and polyurethane.Ad-ditionally,it delves into the associated challenges and prospects,offering researchers valuable insights into the potential value of high-strength SMPs within the domain of 4DP.展开更多
Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomime...Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomimetic scaffold aimed at facilitating rapid and scarless wound healing.This highly in-tegrated 3D-printed dermal scaffold comprised modified recombinant human type III collagen(rhCOLIII-MA),gelatin methacrylate(GelMA),and liposomes encapsulating SB431542 to target TGF-β1(Lip@SB).The rhCOLIII-MA/GelMA(CG)scaffold retained inherent biomaterial characteristics,exhibited tailored physicochemical properties,and demonstrated favorable biocompatibility.Moreover,the Lip@SB-loaded CG scaffold(CGL)effectively promoted in vitro wound healing,while enabling controlled release of SB431542 to inhibit pathological collagen deposition.In a full-thickness skin defect rat model,the CGL dermal scaffold combined with split-thickness skin graft(STSG)minimized scar contraction,stimulated functional neovascularization,and enhanced graft aesthetics comparable to normal skin.Remarkably,the performance of the CGL scaffold surpassed that of commercially available anti-scarring alternatives.This innovative strategy presents a straightforward approach toward scarless skin regeneration and holds promise in alleviating the prolonged,painful postoperative rehabilitation.展开更多
Digital light processing(DLP)is a crucial additive manufacturing(AM)technique for producing high-precision ceramic com-ponents.This study aims to optimize the formulation of Si_(3)N_(4)slurry to enhance both its perfo...Digital light processing(DLP)is a crucial additive manufacturing(AM)technique for producing high-precision ceramic com-ponents.This study aims to optimize the formulation of Si_(3)N_(4)slurry to enhance both its performance and manufacturability in the DLP process,and investigate key factors such as particle size distribution,photopolymer resin monomer ratios,and dispersant types to im-prove the slurry’s rheological properties.Through these optimizations,a photosensitive Si_(3)N_(4)slurry with 50vol%solid content was de-veloped,exhibiting excellent stability,and low viscosity(2.48 Pa·s at a shear rate of 12.8 s^(-1)).The effects of gas-pressure sintering on the material’s phase composition,microstructure,and mechanical properties were further explored,revealing that this technique significantly increases the flexural strength of the green sample from(109±10.24)to(618±42.15)MPa.The sintered ceramics exhibited high hard-ness((16.59±0.05)GPa)and improved fracture toughness((4.45±0.03)MPa·m^(1/2)).Crack trajectory analysis revealed that crack deflec-tion,crack bridging,and the pull-out of rod-likeβ-Si_(3)N_(4)grains,are the main toughening mechanisms,which could effectively mitigate crack propagation.Among these mechanisms,crack deflection and bridging were particularly influential,significantly enhancing the frac-ture toughness of the Si_(3)N_(4)matrix.Overall,this research highlights how monomer formulation and gas-pressure sintering strengthen the performance of Si_(3)N_(4)slurry in the DLP three-dimensional printing technique.This work is expected to provide new insights for fabricat-ing complex Si_(3)N_(4)ceramic components with superior mechanical properties.展开更多
采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨...采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。展开更多
基金the National Natural Science Foundation of China(Nos.52105421 and 52373050)the Guangdong Provincial Natural Science Foundation,China(No.2022A1515011621)+1 种基金the Science and Technology Projects in Guangzhou,China(Nos.202102080330 and 2024A04J6446)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22qntd0101).
文摘Wireless millirobots engineered to infiltrate intricate vascular networks within living organisms,particularly within constricted and confined spaces,hold immense promise for the future of medical treatments.However,with their multifaceted and intricate designs,some robots often grapple with motion and functionality issues when confronted with tight spaces characterized by small cross-sectional dimensions.In this study,drawing inspiration from the high aspect ratio and undulating swimming patterns of snakes,a millimeter-scale,snake-like robot was designed and fabricated via a combination of extrusion-based four-dimensional(4D)printing and magnetic-responsive intelligent functional inks.A sophisticated motion control strategy was also developed,which enables the robots to perform various dynamic movements,such as undulating swimming,precise turns,graceful circular motions,and coordinated cluster movements,under diverse magnetic field variations.As a potential application,the snake robot can navigate and release drugs in a model coronary intervention vessel with tortuous channels and fluid filling.The novel design and promising applications of this snake robot are invaluable tools in future medical surgeries and interventions.
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 National Natural Science Foundation of China(Grant Nos.51935012,52005481)LICP Cooperation Foundation for Young Scholars(Grant No.HZJJ22-11)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0470303)Major Program of the Lanzhou Institute of Chemical Physics,CAS(Grant No.ZYFZFX-7).
文摘“Life”represents a distinctive attribute inherent to organisms in nature,evident in their capacity to actively adapt to changes in their environment.In contrast to the static and intricate constructs of additive manufacturing(AM),the dynamic structure of 4D printing(4DP)adeptly integrates AM technology,responsive mechanisms,and external stimuli,imbuing it with a semblance of“life.”This fusion significantly broadens its functional applica-tions across biomedicine,actuators,and metamaterials.The escalating demand across diverse fields necessitates heightened criteria for 4DP,encompassing rapid response,multi-stimulus response,large shape change,and specific mechanical properties(e.g.,high strength,high modulus)capable of accommodating varying environ-mental conditions.In recent years,shape memory polymers(SMPs)have garnered increasing attention among 4DP researchers due to their ease of design and preprogramming at the molecular level,facilitating controlled transformations along predictable pathways.However,4DP of high-strength SMPs,as an indispensable part of the high-performance field,is full of challenges because the intrinsic properties of the raw materials are not well compatible with the printing principle and the printed configuration is not flexible enough.Consequently,this paper provides a concise overview of the response mechanisms and applications of five prominent high-strength SMPs utilized in 4DP:epoxy resin,poly(ether-ether-ketone),polyimide,polylactic acid,and polyurethane.Ad-ditionally,it delves into the associated challenges and prospects,offering researchers valuable insights into the potential value of high-strength SMPs within the domain of 4DP.
基金supported by the National Natural Science Foundation of China(No.82272297).
文摘Abnormal wound scarring often leads to functional impairments and cosmetic deformities,primarily driven by the prolonged activation of the TGF-β/Smad signaling pathway.Addressing this challenge,we developed a biomimetic scaffold aimed at facilitating rapid and scarless wound healing.This highly in-tegrated 3D-printed dermal scaffold comprised modified recombinant human type III collagen(rhCOLIII-MA),gelatin methacrylate(GelMA),and liposomes encapsulating SB431542 to target TGF-β1(Lip@SB).The rhCOLIII-MA/GelMA(CG)scaffold retained inherent biomaterial characteristics,exhibited tailored physicochemical properties,and demonstrated favorable biocompatibility.Moreover,the Lip@SB-loaded CG scaffold(CGL)effectively promoted in vitro wound healing,while enabling controlled release of SB431542 to inhibit pathological collagen deposition.In a full-thickness skin defect rat model,the CGL dermal scaffold combined with split-thickness skin graft(STSG)minimized scar contraction,stimulated functional neovascularization,and enhanced graft aesthetics comparable to normal skin.Remarkably,the performance of the CGL scaffold surpassed that of commercially available anti-scarring alternatives.This innovative strategy presents a straightforward approach toward scarless skin regeneration and holds promise in alleviating the prolonged,painful postoperative rehabilitation.
基金supported in part by the National Natural Science Foundation of China.(Nos.62461160259,92360307 and 92267103).
文摘Digital light processing(DLP)is a crucial additive manufacturing(AM)technique for producing high-precision ceramic com-ponents.This study aims to optimize the formulation of Si_(3)N_(4)slurry to enhance both its performance and manufacturability in the DLP process,and investigate key factors such as particle size distribution,photopolymer resin monomer ratios,and dispersant types to im-prove the slurry’s rheological properties.Through these optimizations,a photosensitive Si_(3)N_(4)slurry with 50vol%solid content was de-veloped,exhibiting excellent stability,and low viscosity(2.48 Pa·s at a shear rate of 12.8 s^(-1)).The effects of gas-pressure sintering on the material’s phase composition,microstructure,and mechanical properties were further explored,revealing that this technique significantly increases the flexural strength of the green sample from(109±10.24)to(618±42.15)MPa.The sintered ceramics exhibited high hard-ness((16.59±0.05)GPa)and improved fracture toughness((4.45±0.03)MPa·m^(1/2)).Crack trajectory analysis revealed that crack deflec-tion,crack bridging,and the pull-out of rod-likeβ-Si_(3)N_(4)grains,are the main toughening mechanisms,which could effectively mitigate crack propagation.Among these mechanisms,crack deflection and bridging were particularly influential,significantly enhancing the frac-ture toughness of the Si_(3)N_(4)matrix.Overall,this research highlights how monomer formulation and gas-pressure sintering strengthen the performance of Si_(3)N_(4)slurry in the DLP three-dimensional printing technique.This work is expected to provide new insights for fabricat-ing complex Si_(3)N_(4)ceramic components with superior mechanical properties.
文摘采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。
