The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuato...The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.展开更多
Rapid and accurate visible-light photopolymerization is essential for advancing bioprinted engineered tissues.In this study,we developed a novel three-component photoinitiator system for visible light-induced crosslin...Rapid and accurate visible-light photopolymerization is essential for advancing bioprinted engineered tissues.In this study,we developed a novel three-component photoinitiator system for visible light-induced crosslinking of gelatin methacryloyl(GelMA)hydrogels,designed to improve polymerization kinetics,mechanical strength,and structural integrity.Incorporation of 2-bromoacetophenone(BAP)considerably accelerated photopolymerization,with reaction rates increasing alongside BAP concentration,enabling the rapid fabrication of stable hydrogel scaffolds.Printing experiments confirmed that BAP promoted fast crosslinking of GelMA bioinks under visible light,reducing printing time while preserving high-resolution structural features.Additionally,the incorporation of BAP induced microscale structural transformations in the hydrogels during hydration,as evidenced by scanning electron microscopy imaging and swelling analyses.This unique property enabled the fabrication of multilayer constructs exhibiting time-dependent deformation,demonstrating four-dimensional(4 D)printing ca pabilities.Moreover,biocompatibility evaluations revealed that cells maintained high viability in BAP-containing hydrogels.Overall,the BAP-based photoinitiator system offers a promising strategy for high-speed,high-resolution bioprinting,combining enhanced mechanical performance,reduced fabrication time,and dynamic structural adaptability-features that make it highly suitable for advanced biofabrication and tissue engineering applications.展开更多
Digital light processing(DLP)is a high-speed,high-precision 3-dimensional(3D)printing technique gaining traction in the fabrication of ceramic composites.However,when printing 0-3 composites containing lead zirconate ...Digital light processing(DLP)is a high-speed,high-precision 3-dimensional(3D)printing technique gaining traction in the fabrication of ceramic composites.However,when printing 0-3 composites containing lead zirconate titanate(PZT)particles,a widely used piezoelectric ceramic,severe density and refractive index mismatches between the 2 phases pose challenges for ink synthesis and the printing process.Here,we systematically and quantitatively optimized DLP printing of PZT composites,streamlining process development and providing a solid theoretical and experimental foundation for broader applications of DLP technology.PZT particles were pretreated with air plasma to improve slurry uniformity and enhance stress transfer at the composite interface,leading to improved chemical modification,mechanical strength,and piezoelectric properties.We investigated the effects of key process parameters on printability and accuracy by analyzing the curing behavior of PZT–polymer composites.A quantitative model of the DLP curing process was introduced.Unlike stereolithography(SLA),DLP curing depth was found to depend on energy dose and light intensity,with higher intensities proving more favorable for printing 0-3 PZT composites.From depth/width–energy curves,optimal process parameters were determined.We designed and fabricated a soft piezoelectric metamaterial-based touch sensor using these parameters,achieving a customized output profile.This work offers critical insights into optimizing DLP for functional materials and expands the potential of 3D-printed piezoelectric composites.展开更多
Digital light processing(DLP)-based 3D printing technique holds promise in fabricating scaffolds with high precision.Here raw calcium phosphate(CaP)powders were modified by 5.5%monoalcohol ethoxylate phosphate(MAEP)to...Digital light processing(DLP)-based 3D printing technique holds promise in fabricating scaffolds with high precision.Here raw calcium phosphate(CaP)powders were modified by 5.5%monoalcohol ethoxylate phosphate(MAEP)to ensure high solid loading and low viscosity.The rheological tests found that photocurable slurries composed of 50wt%modified CaP powders and 2wt%toners were suitable for DLP printing.Based on geometric models designed by computer-aided design(CAD)system,three printed CaP ceramics with distinct macroporous structures were prepared,including simple cube,octet-truss and inverse face-centered cube(fcc),which presented the similar phase composition and microstructure,but the different macropore geometries.Inverse fcc group showed the highest porosity and compressive strength.The in vitro and in vivo biological evaluations were performed to compare the bioactivity of three printed CaP ceramics,and the traditional foamed ceramic was used as control.It suggested that all CaP ceramics exhibited good biocompatibility,as evidence by an even bone-like apatite layer formation on the surface,and the good cell proliferation and spreading.A mouse intramuscular implantation model found that all of CaP ceramics could induce ectopic bone formation,and foam group had the strongest osteoinduction,followed by inverse fcc,while cube and octet-truss had the weakest one.It indicated that macropore geometry was of great importance to affect the osteoinductivity of scaffolds,and spherical,concave macropores facilitated osteogenesis.These findings provide a strategy to design and fabricate high-performance orthopedic grafts with proper pore geometry and desired biological performance via DLP-based 3D printing technique.展开更多
A polymer based horizontal single step waveguide fbr the sensing of alcohol is developed and analyzed.The waveguide is fabricated by 3-dimensional(3D)printing digital light processing(DLP)technology using monocure 3D ...A polymer based horizontal single step waveguide fbr the sensing of alcohol is developed and analyzed.The waveguide is fabricated by 3-dimensional(3D)printing digital light processing(DLP)technology using monocure 3D rapid ultraviolet(UV)clear resin with a refractive index of n=1.50.The fabricated waveguide is a one-piece tower shaped ridge structure.It is designed to achieve the maximum light confinement at the core by reducing the effective refractive index around the cladding region.With the surface roughness generated from the 3D printing DLP technology,various waveguides with different gap sizes are printed.Comparison is done fbr the different gap waveguides to achieve the minimum feature gap size utilizing the light re-coupling principle and polymer swelling effect.This effect occurs due to the polymer-alcohol interaction that results in the diffusion of alcohol molecules inside the core of the waveguide,thus changing the waveguide from the leaky type(without alcohol)to the guided type(with alcohol).Using this principle,the analysis of alcohol concentration performing as a larger increase in the transmitted light in tensity can be measured.In this work,the sensitivity of the system is also compared and analyzed fbr different waveguide gap sizes with different concentrations of isopropanol alcohol(IPA).A waveguide gap size of 300 jim gives the highest in crease in the transmitted optical power of 65%when tested with 10μL(500ppm)concentration of IPA.Compared with all other gaps,it also displays faster response time(/=5seconds)fbr the optical power to change right after depositing IPA in the chamber.The measured limit of detection(LOD)achieved fbr 300μm is 0.366 yL.In addition,the fabricated waveguide gap of 300μm successfully demonstrates the sen sing limit of IPA concentration below 400μpm which is considered as an exposure limit by"National Institute for Occupational Safety and Health".All the mechanical mount and the alignments are done by 3D printing fused deposition method(FDM).展开更多
基金the National Natural Science Foundation of China(Nos.11572002 and 12002032)the China Postdoctoral Science Foundation(Nos.BX20200056 and 2020M670149)。
文摘The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery Grant(No.RGPIN-2020-04559)the Canada Foundation for Innovation John R.Evans Leaders Fund(JELF).
文摘Rapid and accurate visible-light photopolymerization is essential for advancing bioprinted engineered tissues.In this study,we developed a novel three-component photoinitiator system for visible light-induced crosslinking of gelatin methacryloyl(GelMA)hydrogels,designed to improve polymerization kinetics,mechanical strength,and structural integrity.Incorporation of 2-bromoacetophenone(BAP)considerably accelerated photopolymerization,with reaction rates increasing alongside BAP concentration,enabling the rapid fabrication of stable hydrogel scaffolds.Printing experiments confirmed that BAP promoted fast crosslinking of GelMA bioinks under visible light,reducing printing time while preserving high-resolution structural features.Additionally,the incorporation of BAP induced microscale structural transformations in the hydrogels during hydration,as evidenced by scanning electron microscopy imaging and swelling analyses.This unique property enabled the fabrication of multilayer constructs exhibiting time-dependent deformation,demonstrating four-dimensional(4 D)printing ca pabilities.Moreover,biocompatibility evaluations revealed that cells maintained high viability in BAP-containing hydrogels.Overall,the BAP-based photoinitiator system offers a promising strategy for high-speed,high-resolution bioprinting,combining enhanced mechanical performance,reduced fabrication time,and dynamic structural adaptability-features that make it highly suitable for advanced biofabrication and tissue engineering applications.
基金supported by the National Natural Science Foundation of China(grant no.12072143)the Science,Technology and Innovation Commission of Shenzhen Municipality(grant no.ZDSYS20210623092005017)the Stable Support Plan Program of Shenzhen Natural Science Fund(grant no.20200925155345003).
文摘Digital light processing(DLP)is a high-speed,high-precision 3-dimensional(3D)printing technique gaining traction in the fabrication of ceramic composites.However,when printing 0-3 composites containing lead zirconate titanate(PZT)particles,a widely used piezoelectric ceramic,severe density and refractive index mismatches between the 2 phases pose challenges for ink synthesis and the printing process.Here,we systematically and quantitatively optimized DLP printing of PZT composites,streamlining process development and providing a solid theoretical and experimental foundation for broader applications of DLP technology.PZT particles were pretreated with air plasma to improve slurry uniformity and enhance stress transfer at the composite interface,leading to improved chemical modification,mechanical strength,and piezoelectric properties.We investigated the effects of key process parameters on printability and accuracy by analyzing the curing behavior of PZT–polymer composites.A quantitative model of the DLP curing process was introduced.Unlike stereolithography(SLA),DLP curing depth was found to depend on energy dose and light intensity,with higher intensities proving more favorable for printing 0-3 PZT composites.From depth/width–energy curves,optimal process parameters were determined.We designed and fabricated a soft piezoelectric metamaterial-based touch sensor using these parameters,achieving a customized output profile.This work offers critical insights into optimizing DLP for functional materials and expands the potential of 3D-printed piezoelectric composites.
基金sponsored by the National Key Research and Development Program of China(2017YFB0702600)National Natural Science Foundation of China(31971283,31670985)Sichuan Science and Technology Programs(2019JDTD0008,2021YFS0032).
文摘Digital light processing(DLP)-based 3D printing technique holds promise in fabricating scaffolds with high precision.Here raw calcium phosphate(CaP)powders were modified by 5.5%monoalcohol ethoxylate phosphate(MAEP)to ensure high solid loading and low viscosity.The rheological tests found that photocurable slurries composed of 50wt%modified CaP powders and 2wt%toners were suitable for DLP printing.Based on geometric models designed by computer-aided design(CAD)system,three printed CaP ceramics with distinct macroporous structures were prepared,including simple cube,octet-truss and inverse face-centered cube(fcc),which presented the similar phase composition and microstructure,but the different macropore geometries.Inverse fcc group showed the highest porosity and compressive strength.The in vitro and in vivo biological evaluations were performed to compare the bioactivity of three printed CaP ceramics,and the traditional foamed ceramic was used as control.It suggested that all CaP ceramics exhibited good biocompatibility,as evidence by an even bone-like apatite layer formation on the surface,and the good cell proliferation and spreading.A mouse intramuscular implantation model found that all of CaP ceramics could induce ectopic bone formation,and foam group had the strongest osteoinduction,followed by inverse fcc,while cube and octet-truss had the weakest one.It indicated that macropore geometry was of great importance to affect the osteoinductivity of scaffolds,and spherical,concave macropores facilitated osteogenesis.These findings provide a strategy to design and fabricate high-performance orthopedic grafts with proper pore geometry and desired biological performance via DLP-based 3D printing technique.
文摘A polymer based horizontal single step waveguide fbr the sensing of alcohol is developed and analyzed.The waveguide is fabricated by 3-dimensional(3D)printing digital light processing(DLP)technology using monocure 3D rapid ultraviolet(UV)clear resin with a refractive index of n=1.50.The fabricated waveguide is a one-piece tower shaped ridge structure.It is designed to achieve the maximum light confinement at the core by reducing the effective refractive index around the cladding region.With the surface roughness generated from the 3D printing DLP technology,various waveguides with different gap sizes are printed.Comparison is done fbr the different gap waveguides to achieve the minimum feature gap size utilizing the light re-coupling principle and polymer swelling effect.This effect occurs due to the polymer-alcohol interaction that results in the diffusion of alcohol molecules inside the core of the waveguide,thus changing the waveguide from the leaky type(without alcohol)to the guided type(with alcohol).Using this principle,the analysis of alcohol concentration performing as a larger increase in the transmitted light in tensity can be measured.In this work,the sensitivity of the system is also compared and analyzed fbr different waveguide gap sizes with different concentrations of isopropanol alcohol(IPA).A waveguide gap size of 300 jim gives the highest in crease in the transmitted optical power of 65%when tested with 10μL(500ppm)concentration of IPA.Compared with all other gaps,it also displays faster response time(/=5seconds)fbr the optical power to change right after depositing IPA in the chamber.The measured limit of detection(LOD)achieved fbr 300μm is 0.366 yL.In addition,the fabricated waveguide gap of 300μm successfully demonstrates the sen sing limit of IPA concentration below 400μpm which is considered as an exposure limit by"National Institute for Occupational Safety and Health".All the mechanical mount and the alignments are done by 3D printing fused deposition method(FDM).
