Magnetically Guided Nanorobotic Swarms for Targeted Biomarker Navigation in Dynamic Vascular Environments

Targeted therapeutic delivery in microvascular networks is constrained by hemodynamic drag forces, shear stress variability, and limited spatial maneuvering at sub-micron scales. We present a swarm-based control framework for magnetically guided nanorobotic agents navigating complex fluid channels. The system integrates global electromagnetic field actuation with localized chemical gradient sensing, enabling decentralized swarm aggregation around targeted tumor biomarkers. A dynamic fluid-structure interactions simulator evaluates swarm retention across five operational blood flow velocities: nominal venous flow, elevated arterial shear, microvascular tortuosity, vascular occlusion, and high-drift shear streams. Across five fixed random seeds, the proposed hybrid magnetic-chemotactic policy achieved a 91.4% biomarker targeting retention rate (1.6%) compared with 71.2% (2.8%) for purely magnetic field guidance.