A Dynamic Yolk-Shell p-n Heterojunction With Coupled Shear Stress-Triggered Tribo-/Piezoelectric Effect for Catalytic...

Arterial thrombosis is a major cause of cardiovascular mortality, yet thrombolytic agents are limited by recurrence and bleeding risks. Non-pharmacological methods using photo-/sono-dynamic effects require external stimuli and high mechanic force. Herein, we propose a yolk-shell-structured p-n dynamic heterojunction that, in response to increased shear stress at clot sites, interfacial collisions between the yolk and shell generate tribo-/piezoelectric catalysis, producing reactive oxygen species (ROS) for thrombolysis. Specifically, yolk-shell BFO@tBT-C nanoparticles were fabricated by sequentially depositing sacrificial SiO₂ and TiO₂ layers on BiFeO₃ (BFO) yolks, with thrombus-targeting peptides grafted onto the tetragona BaTiO₃ (tBT) shell. The coupled tribo-/piezoelectric effect generates 3.6 and 2.1-folds higher potentials than individual triboelectric and piezoelectric potentials, respectively. An interfacial electric field (IEF) between BFO and tBT, along with piezoelectric fields (PEF), facilitates the separation of electron-hole pairs, and the transient electric field (TEF) formed after yolk-shell separation promotes the cleavage of O-H bonds in H₂O and the diffusion of ·O₂ ^-, amplifying ROS generation. The grafted thrombus-targeting peptides increase nanoparticle accumulation at the clot site by 3-fold, while the shear-responsive mechanism minimizes off-target effects. Thus, by integrating endogenous shear stress-responsiveness and dynamic heterojunction engineering, this work pioneers a transformative approach for precise, high-efficacy thrombolysis.