Centering mechanism for micro vessel robot using micropatterned shape memory polymers

Coronary artery disease refers to a variety of illnesses including angina pectoris, myocardial infarction, and other types of coronary artery disorders. Recently, there has been a significant increase in the incidence of these coronary artery diseases in part due to changes in eating habits, environmental pollution and mental stress. To address this issue, percutaneous coronary intervention (PCI) technology has been developed with remarkable advances in a range of surgery devices. However, some clinical operations, such as the treatment of chronic total occlusion (CTO), remain challenging because the fibro-calcific plaque of CTO hinders smooth navigation of a PCT catheter inside the coronary artery. This paper proposes a conceptual design of the centering mechanism of a micro-robot utilizing three-leg polymer arms and micropatterned polymer adhesives. In particular, shape memory polymer (SMP) actuators were used to exert a force on the vessel wall in the micro-robot arms. Micropatterned-thin suction pads were fabricated on the surface of micro-robot arms to increase the adhesion and friction force of micro-robot arms against the blood vessel. Our experimental findings demonstrate that the proposed centering mechanism is effective in maintaining the proper position of the micro-robot in the coronary artery and is potentially capable of providing a smart, self-navigating micro-robot for coronary artery diseases with sufficient traction force to maintain a precise centering location in the coronary artery.