1 Bioinspired Engineering and Biomechanics Center (BEBC), the Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China, and the Department of Mechanical Engineering and Materials Science, School of Engineering and Applied Science, and the Department of Neurological Surgery at Washington University in St Louis, Missouri 63130, USA.
2 Department of Orthopedic Surgery, and the Department of Biomedical Engineering at Columbia University, New York 10032, USA.
High-resolution imaging, composition analysis and mechanical testing reveal a disordered transitional material within the Achilles tendon-to-bone attachment, structured as a fibrous network to enable force transfer and maximize structural integrity.