A Hybrid Magnetic Actuation System for Single‐Input Multistates Stabilization: Application to pH‐Responsive Drug Delivery

Abstract

Targeted drug delivery requires precise carrier navigation and controlled payload release. We present an integrated robotic platform that combines a hybrid magnetic array with a pH‐responsive soft hydrogel. The array achieves single‐input, multistate stabilization: one current input actively regulates the z ‐axis equilibrium, while the x , y , ϕ , and θ states passively converge through an optimized magnetic potential‐energy landscape. Translating the array along x , y , and z , changing its azimuth provides intuitive 4‐DOF manipulation; an additional current‐redistribution parameter shifts the equilibrium to enable limited θ manipulation, yielding semi‐5‐DOF performance. The system achieves submillimeter positioning in low‐viscosity water. The hydrogel provides passive, pH‐triggered detachment under acidic conditions without additional external actuation. In a simplified pH 2 aqueous environment representing only the acidic‐pH aspect of gastric conditions, the platform completes magnetic transport, hydrogel detachment, and capsule retrieval. These results demonstrate the operational feasibility of integrating precise magnetic navigation with environment‐responsive release and provide a foundation for future targeted‐delivery robotic systems.