A magnetically controlled flexible microrobot for active and precise guidewire steering

Abstract

Guidewires are highly engineered medical devices that form an integral part of minimally invasive vascular interventions. They are used to gain access to target lesions in the blood vessels and guide other medical devices to deliver interventional treatment. However, their steering and navigation in tortuous and constrained vascular environments is often limited by manual control performed by physicians. Moreover, fluoroscopy (i.e., X-ray imaging) is considered an essential part of the procedure despite causing serious radiation hazards to both patients and the medical crew. To alleviate the problems, we propose a microrobotic approach that involves the use of a flexible magnetic microrobot integrated with a conventional guidewire, improving the steerability of the guidewire in complex vascular structures via magnetic torque under an external magnetic field. The microrobot is composed of ferromagnetic materials encapsulated in a biocompatible silicone tube and coated with hydrophilic materials to reduce the surface friction while navigating through the vessels. The active magnetic steering and navigation capability of the microrobot was demonstrated in vascular phantom models in vitro, where the results showed that the microrobot helped the guidewire precisely navigate to the designated targets in a selective manner with a maximum steering angle over 90 degrees. Further in vivo studies in peripheral and coronary arteries of a swine confirmed the potential clinical benefits of magnetic steering of the microrobot in complex vascular environments. The integration of the proposed microrobot with imaging and magnetic control systems holds great promise for various interventional applications, assisting medical physicians with guidewire manipulation to reach target lesions more efficiently and safely than ever before.