Shear Stress Modeling and Machine Learning for Nanomedicine Development: A Mechanistic Pathway to Pharmacokinetic...

Clinical translation of nanomedicines remains constrained by a persistent gap between static preclinical assays and the dynamic shear environment of the human vasculature. This review argues that fluid shear stress is an underappreciated contributor to clinical attrition, acting alongside well-established factors including biomarker-target mismatch, enhanced permeability and retention heterogeneity, preclinical-clinical discordance in tumor biology, and manufacturing variability. Circulating nanocarriers traverse a mechanical environment in which wall shear stress spans from 0.1 dyn/cm2 in hepatic sinusoids to over 1000 dyn/cm2 in stenotic regions. Emerging quantitative studies indicate that these forces can modulate carrier stability, protein-corona composition, and drug release in ways that static in vitro assays cannot resolve, with the cholesterol-rigidified bilayer of Doxil and the shear-activated platforms of Korin and colleagues providing representative positive control and mechanistic evidence. We synthesize recent progress at the interface of computational fluid dynamics and machine learning. Physics-informed neural networks, deep operator networks, and graph neural networks feature prominently in this synthesis and underpin an integrated framework for mechanistically informed pharmacokinetic prediction. Reported benchmarks show surrogate models reconstructing hemodynamic fields with under 5% error relative to high-fidelity CFD while reducing data requirements 5- to 10-fold, and convolutional surrogates trained on approximately 1800 patient-specific simulations predicting time-averaged wall shear stress with 2.5% mean absolute error. These surrogate models integrate hemodynamic descriptors (TAWSS, OSI, and RRT) with distributional particle features (D10, D50, and D90). We outline the evidentiary and methodological path toward biomechanically informed nanomedicine development aligned with emerging regulatory frameworks, while acknowledging that routine regulatory acceptance of computational shear modeling remains a future milestone rather than current practice.