Twisted carbon nanotubes make ideal replacements for damaged ligaments

An artificial ligament that integrates more strongly with the host’s bone than the best clinical material has been created using intertwined carbon nanotubes. When the nanotube ligament was transplanted into the legs of rabbits and sheep, they were able to run and jump normally once they had healed from the surgery.

Ligaments connect bones together, and must withstand high longitudinal stress while remaining flexible. Natural ligaments comprise a rope-like hierarchy of nanometre-scale fibrils of collagen intertwined to form micrometre-scale fibres that are twisted into subfascicular bundles. When ligaments fail completely, finding replacements is challenging. A surgeon’s first choice is usually harvesting a tendon from the patient’s own body, but this can cause problems at the donor site. Alternatively, a cadaver can be used, but this poses potential – albeit manageable – risks of rejection or disease transmission, as well as restricted availability.