Native heart valve leaflets with layered fibrous structures show anisotropic characteristics,allowing them to withstand complex mechanical loading for long-term cardiac cycles.Herein,two types of silk fibroin(SF)fiber...Native heart valve leaflets with layered fibrous structures show anisotropic characteristics,allowing them to withstand complex mechanical loading for long-term cardiac cycles.Herein,two types of silk fibroin(SF)fiber membranes with anisotropic(ASF)and isotropic(ISF)properties were prepared by electrospinning,and were further combined with poly(ethylene glycol)diacrylate(PEGDA)hydrogels to serve as polymeric heart valve(PHV)substitutes(PEGDA-ASF and PEGDA-ISF).The uniaxial tensile tests showed obvious anisotropy of PEGDA-ASF with elastic moduli of 10.95±1.09 and3.55±0.32 MPa,respectively,along the directions parallel and perpendicular to the fiber alignment,while PEGDA-ISF possessed isotropic property with elastic moduli of 4.54±0.43 MPa.The PHVs from both PEGDA-ASF and PEGDA-ISF presented appropriate hydrodynamic properties from pulse duplicator tests according to the ISO 5840-3 standard.However,finite element analysis(FEA)revealed the anisotropic PEGDA-ASF valve showed a lower maximum principle stress value(2.20 MPa)in commissures during diastole compared with that from the isotropic PEGDA-ISF valve(2.37 MPa).In the fully open state,the bending area of the PEGDA-ASF valve appeared in the belly portion and near the attachment line like native valves,however,which was close to free edges for the PEGDA-ISF valve.The Gauss curvature analysis also indicated that the anisotropic PEGDA-ASF valve can produce appropriate surface morphology by dynamically adjusting the movement of bending area during the opening process.Hence,anisotropy of PHVs with bio-inspired layered fibrous struc-tures played important roles in mechanical and hydrodynamic behavior mimicking native heart valves.展开更多
基金supported by the National Natural Science Foundation of China (31300788)the Hundred-Talent Program from Chinese Academy of Sciences
文摘Native heart valve leaflets with layered fibrous structures show anisotropic characteristics,allowing them to withstand complex mechanical loading for long-term cardiac cycles.Herein,two types of silk fibroin(SF)fiber membranes with anisotropic(ASF)and isotropic(ISF)properties were prepared by electrospinning,and were further combined with poly(ethylene glycol)diacrylate(PEGDA)hydrogels to serve as polymeric heart valve(PHV)substitutes(PEGDA-ASF and PEGDA-ISF).The uniaxial tensile tests showed obvious anisotropy of PEGDA-ASF with elastic moduli of 10.95±1.09 and3.55±0.32 MPa,respectively,along the directions parallel and perpendicular to the fiber alignment,while PEGDA-ISF possessed isotropic property with elastic moduli of 4.54±0.43 MPa.The PHVs from both PEGDA-ASF and PEGDA-ISF presented appropriate hydrodynamic properties from pulse duplicator tests according to the ISO 5840-3 standard.However,finite element analysis(FEA)revealed the anisotropic PEGDA-ASF valve showed a lower maximum principle stress value(2.20 MPa)in commissures during diastole compared with that from the isotropic PEGDA-ISF valve(2.37 MPa).In the fully open state,the bending area of the PEGDA-ASF valve appeared in the belly portion and near the attachment line like native valves,however,which was close to free edges for the PEGDA-ISF valve.The Gauss curvature analysis also indicated that the anisotropic PEGDA-ASF valve can produce appropriate surface morphology by dynamically adjusting the movement of bending area during the opening process.Hence,anisotropy of PHVs with bio-inspired layered fibrous struc-tures played important roles in mechanical and hydrodynamic behavior mimicking native heart valves.
