Modulation of Cilia Motility by Vortex-Ultrasound-Induced Shear Stress

The precise and noninvasive modulation of primary ciliary mechanotransduction remains a significant challenge in cell biology. Current approaches induce cilia motility─including microfluidic flow, optical tweezers, magnetic actuation, and genetic or optogenetic techniques─are constrained by low spatiotemporal precision and poor suitability for in vivo applications. Here, we present a noninvasive approach using vortex ultrasound (VUS) to generate localized shear stress via helical acoustic streaming. Using a 3.5 MHz transducer, VUS-generated shear stresses were approximately 5-fold higher than for conventional focused ultrasound, inducing cilia deflections of up to 80°. This mechanical stimulation triggered cilia-dependent calcium influx via ciliary ion channels, including transient receptor potential vanilloid 4 (TRPV4) and transient receptor potential polycystin 2 (TRPP2), demonstrating the direct activation of primary ciliary mechanotransduction by VUS-induced shear stress. These findings indicate VUS is a powerful tool for ciliary mechanobiology that can offer a scalable physical modality for investigating and manipulating cilia-associated signaling pathways in intact biological systems.