ABSTRACT Melt electrowriting(MEW)enables the precise deposition of polymeric fibers at micro-/nanoscale,allowing for the fabrication of 3D biomimetic scaffolds.By incorporating stimuli-responsive polymers and/or funct...ABSTRACT Melt electrowriting(MEW)enables the precise deposition of polymeric fibers at micro-/nanoscale,allowing for the fabrication of 3D biomimetic scaffolds.By incorporating stimuli-responsive polymers and/or functional fillers,MEW-based 4D printing creates scaffolds capable of undergoing controlled,reversible shape transformations in response to external stimuli over time.These dynamic 4D scaffolds can be tailored for minimally invasive delivery,remote actuation,and real-time responsiveness to physiological environments,making them highly relevant for biomedical applications.This review systematically elucidates the principles of MEW-based 4D printing,including material considerations,actuation methods,and structure design strategies,along with shape programming and morphing mechanisms.The versatility of MEW for rational fabrication of biomimetic scaffolds is firstly introduced.Subsequently,the critical elements underpinning MEW-based 4D printing process are overviewed,including an analysis of stimuli-responsive materials compatible with MEW,an evaluation of applicable external stimuli,and a discussion on the advancements in design strategies for 4D scaffolds.Recent progress of MEW 4D scaffolds for applications in tissue engineering,biomedical implants,and drug delivery systems are highlighted.Finally,key challenges and perspectives toward material innovation,fabrication optimization,and actuation control are discussed.This review aims to provide valuable insights for design and creation of multifunctional biomimetic dynamic scaffolds by MEW-based 4D printing.展开更多
Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability...Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12302422,12572342)Marie Sklodowska-Curie grant agreement ENSIGN(101086226),NanoRam(101120146)and L4DNANO(101086227).
文摘ABSTRACT Melt electrowriting(MEW)enables the precise deposition of polymeric fibers at micro-/nanoscale,allowing for the fabrication of 3D biomimetic scaffolds.By incorporating stimuli-responsive polymers and/or functional fillers,MEW-based 4D printing creates scaffolds capable of undergoing controlled,reversible shape transformations in response to external stimuli over time.These dynamic 4D scaffolds can be tailored for minimally invasive delivery,remote actuation,and real-time responsiveness to physiological environments,making them highly relevant for biomedical applications.This review systematically elucidates the principles of MEW-based 4D printing,including material considerations,actuation methods,and structure design strategies,along with shape programming and morphing mechanisms.The versatility of MEW for rational fabrication of biomimetic scaffolds is firstly introduced.Subsequently,the critical elements underpinning MEW-based 4D printing process are overviewed,including an analysis of stimuli-responsive materials compatible with MEW,an evaluation of applicable external stimuli,and a discussion on the advancements in design strategies for 4D scaffolds.Recent progress of MEW 4D scaffolds for applications in tissue engineering,biomedical implants,and drug delivery systems are highlighted.Finally,key challenges and perspectives toward material innovation,fabrication optimization,and actuation control are discussed.This review aims to provide valuable insights for design and creation of multifunctional biomimetic dynamic scaffolds by MEW-based 4D printing.
基金supported by the National Natural Science Foundation of China(Nos.52473080,52403167 and 52173079)the Fundamental Research Funds for the Central Universities(Nos.xtr052023001 and xzy012023037)+1 种基金the Postdoctoral Research Project of Shaanxi Province(No.2024BSHSDZZ054)the Shaanxi Laboratory of Advanced Materials(No.2024ZY-JCYJ-04-12).
文摘Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.
