TY - JOUR
T1 - Bi-material nanofibrous electrospun junctions
T2 - A versatile tool to mimic the muscle–tendon interface
AU - Sensini, Alberto
AU - D'Anniballe, Riccardo
AU - Gotti, Carlo
AU - Marchiori, Gregorio
AU - Giavaresi, Gianluca
AU - Carloni, Raffaella
AU - Letizia Focarete, Maria
AU - Zucchelli, Andrea
N1 - Funding Information:
This work was funded by the European Commission's Horizon 2020 Programme as part of the project MAGNIFY under grant no. 801378 (this work was done while A. Sensini was within the Department of Industrial Engineering, University of Bologna, Italy). Horizon Europe Marie Sk\u0142odowska-Curie Postdoctoral Fellowship (Grant No. 101061826 3NTHESES project) is also acknowledged. Lorenzo De Bellis, Laura Pozzi, and Federica Daus are acknowledged for their help in preparing specimens, data elaboration, and training in the water contact angle tests.
Publisher Copyright:
© 2024 The Author(s)
PY - 2024/6/1
Y1 - 2024/6/1
N2 - Soft robotics aims to replicate the structure and mechanics of skeletal muscles. The challenge lies in seamlessly integrating these muscle-inspired soft actuators with the joints they intend to actuate, resembling the natural connection between muscles and tendons (i.e., myotendinous junction). This study addresses this issue by producing electrospun bundles of aligned nanofibers using a thermoplastic polyurethane, mimicking the muscle fascicle, and nylon 6.6 for the tendon one. A novel method was developed to create electrospun bi-material bundles with two different types of myotendinous-inspired junctions, called flat and conical. Scanning electron microscopy and microtomography analyses confirmed that conical junctions mimicked natural myotendinous structures better than flat ones. Tensile mechanical tests demonstrated that bi-material junctions reached stress at failure comparable to polyurethane bundles (11 ± 2 MPa), with the conical junction showing stiffness (0.13 ± 0.02 N/mm) and net elastic modulus (153 ± 10 MPa) values closer to the natural myotendinous ones. Cyclic tests verified the mechanical stability of junctions and their ability to dampen nylon 6.6 hardening over time. Moreover, all bundles withstood cyclic loading without breaking. These findings suggest the potential of biomimetic electrospun junctions for applications in soft robotics, marking a significant step toward advancing this field.
AB - Soft robotics aims to replicate the structure and mechanics of skeletal muscles. The challenge lies in seamlessly integrating these muscle-inspired soft actuators with the joints they intend to actuate, resembling the natural connection between muscles and tendons (i.e., myotendinous junction). This study addresses this issue by producing electrospun bundles of aligned nanofibers using a thermoplastic polyurethane, mimicking the muscle fascicle, and nylon 6.6 for the tendon one. A novel method was developed to create electrospun bi-material bundles with two different types of myotendinous-inspired junctions, called flat and conical. Scanning electron microscopy and microtomography analyses confirmed that conical junctions mimicked natural myotendinous structures better than flat ones. Tensile mechanical tests demonstrated that bi-material junctions reached stress at failure comparable to polyurethane bundles (11 ± 2 MPa), with the conical junction showing stiffness (0.13 ± 0.02 N/mm) and net elastic modulus (153 ± 10 MPa) values closer to the natural myotendinous ones. Cyclic tests verified the mechanical stability of junctions and their ability to dampen nylon 6.6 hardening over time. Moreover, all bundles withstood cyclic loading without breaking. These findings suggest the potential of biomimetic electrospun junctions for applications in soft robotics, marking a significant step toward advancing this field.
KW - Bioinspired junctions
KW - Electrospinning
KW - Mechanical tensile and cyclic tests
KW - microCT
KW - Myotendinous junction
KW - Polyurethane and nylon 6.6
U2 - 10.1016/j.matdes.2024.113015
DO - 10.1016/j.matdes.2024.113015
M3 - Article
SN - 0264-1275
VL - 242
JO - Materials & design
JF - Materials & design
M1 - 113015
ER -