A reconfigurable, healable and recyclable 3D printed orthosis for adolescent idiopathic scoliosis

Abstract

Adolescent idiopathic scoliosis (AIS) is a structural illness, which causes both mental and physical pain in patients. Nowadays, 3D-printed scoliosis orthoses are effective in AIS treatment. Owing to the change in the body shape during orthopedic procedures, a complete course of treatment will need many orthoses to fit patients, which will increase medical expense and result in a large amount of nondegradable waste, thereby polluting the environment. Therefore, reconfigurable and recyclable 3D printed orthoses are desirable. However, the design of materials for such orthoses is fundamentally challenging. Herein, by incorporating disulfide bonds into a bifunctional photoactive acrylate monomer and using dithiothreitol to accelerate disulfide bond exchange, we obtained a stiff yet reconfigurable, recyclable, healable polymer that can be 3D printed into orthoses. This as-prepared polymer demonstrated a high mechanical strength (363.2 MPa Young's modulus and 146.3% maximum elongation) and excellent dynamic properties (reprocessable at 100 °C, recyclable upon dissolving in thiol-containing solvents, and healable upon heating). Orthoses manufactured via the 3D printing of this polymer can adapt to a patient's body through continuous reconfiguration, thus improving their effectiveness in treating AIS. Moreover, these orthoses can be recycled after use, and thus, medical waste can be significantly reduced.