Piezoelectric Micro-Crawlers for Minimally Invasive Endovascular Intervention

Interventional neuroradiology relies heavily on manual catheter guidance through tortuous arterial trees. Catheter buckling, vascular spasm, and friction limitations restrict manual access to distal micro-vessels. Untethered and semi-tethered piezoelectric micro-crawlers solve this by actively walking along lumen surfaces.

1. The Stick-Slip Actuation Principle

Stick-slip locomotion utilizes an asymmetric saw-tooth voltage profile applied to piezoelectric lead zirconate titanate (PZT) ceramic elements. During the slow expansion phase, frictional anchoring against the arterial intima pushes the body forward ("stick"). During the rapid contraction phase, inertial forces overcome dynamic friction, snapping the actuator backward while the main chassis remains stationary ("slip").

2. Biocompatible Micro-Gripper Arrays

To prevent intimal tears, micro-crawlers feature biomimetic gecko-inspired micro-pillar pads composed of polydimethylsiloxane (PDMS). These pads exploit van der Waals forces to generate substantial traction against moist endothelial surfaces without penetrating the elastic lamina.