Twisted and Coiled Carbon Nanotube Yarn Muscle Embedding Ferritin

Electrochemical coiled carbon nanotube yarn muscles are expected to be utilized in biosensors, drug delivery, or microsurgery. However, their low tensile actuation due to the limited applying voltage in an aqueous environment restricts further investigations in applications. Here, by embedding an iron-containing protein, called ferritin into a coiled carbon nanotube yarn muscle, the muscle stroke can be increased 10.8 times. The increased tensile contraction originates from the large electrochemical applied potential without cancellation of the stroke resulting from the potential of zero charge shift which is driven by attaching charged ferritins onto CNTs. Performance enhancement by applying biocompatible molecules encourages the potential of the coiled CNT muscle's use in the bio-environment.