Spatiotemporal Pathway Control for Targeted Drug Delivery: Unified Waveform Modulation in Molecular Communication.

Precise control of drug delivery requires coordination across multiple stages, including release timing, propagation dynamics, and targeting efficiency. To address this, a unified waveform modulation framework inspired by molecular communication (MC), under the broader concept of nanoparticle beamforming (NPB), is proposed to enable full-chain control over nanoparticle (NP) behavior from release through propagation to reception. Within this framework, pathway optimization is considered a key component of channel-level pathway control and is implemented via magnetic-field-assisted navigation. The framework supports NPB-mediated therapeutic-window regulation across diverse pathways, enabling safe and efficient delivery. Magnetic navigation is embedded with spatiotemporal pathway control into channel-level routing to guide NPs through the vascular network. COMSOL Multiphysics simulations are used to model NP motion under magnetic spatiotemporal pathway control conditions. Two representative drugs with contrasting therapeutic windows, Digoxin (narrow window) and Ibuprofen (wide window), are used as case studies to evaluate the adaptability of the framework. Key evaluation metrics include maintaining the localized drug concentration between the minimum effective concentration (MEC) and the minimum toxic concentration (MTC). The COMSOL simulations indicate that magnetic-field-assisted pathway control can improve NP accumulation at the target region, with a 75.3% increase in successful targeting rate compared to the case without magnetic-field control. When integrated into the waveform modulation framework, this pathway optimization helps maintain drug concentrations within the therapeutic window for both case studies. For Ibuprofen, effective levels are sustained over a wide range, while for Digoxin, the system supports tighter regulation to reduce the risk of toxicity. These results suggest the potential of waveform modulation as a unifying control paradigm for drug delivery across the release, propagation, and target stages. Implementing magnetic pathway control at the channel level supports the applicability of the framework under the modeled vascular constraints. The results suggest its potential for generalizable, personalized delivery strategies across diverse therapeutic scenarios.