Ultra-Low Profile $\mu$ Robot-Driven Guidewire for Steerable Neurointerventional Procedure

This paper presents an ultra-low profile (tip size ~ 300$\mu \mathrm{m}$) guidewire, which is wirelessly powered and steered by acoustically driven microswimming robots. The present prototype experimentally demonstrates an unprecedented steering capability of up to 135° bending within$2-\text{mm}$wide phantom vascular branches, offering the following unique advantages: (1) sufficient steering forces (several tens$\mu \mathrm{N}$) despite its small size; (2) the first demonstration of guidewire steering capability using an external, compact, cost-effective, safe ultrasound (US) actuator, as opposed to the magnetic guidewire, which necessitates bulky, expensive, strong (potentially harmful) magnetic field generators (e.g., MRI). This steering capability in tight vascular spaces can potentially facilitate navigation through tortuous and complex neurovascular anatomy, thereby reducing procedure time and improving safety in neurointerventional procedures.