EXPLOITING RECEPTOR NANOCLUSTERS TO BIAS CLATHRIN VS. CAVEOLIN UPTAKE: MOLECULAR DESIGN RULES FOR TARGETED ANTI-CANCER NANOMEDICINES

Abstract

Targeted nanomedicine has advanced beyond cell-specific binding toward the deliberate programming of cellular entry pathways. A central determinant of endocytic pathway selection is receptor nano-clustering, a dynamic process governed by multivalent ligand interactions, membrane lipid organization, and cytoskeletal constraints. This work outlines molecular design principles for engineering nanoparticles that bias uptake toward clathrin-mediated or caveolin-mediated endocytosis. Evidence across model systems suggests that nanoparticles in the 30-80 nm size range with moderate-to-high ligand densities (~10-100 ligands per particle or ~0.01-0.1 ligands nm⁻²) typically promote receptor aggregation sufficient for clathrin-mediated endocytosis (CME) through adaptor protein recruitment and progressive membrane curvature. Particles of approximately 50-150 nm, particularly those presenting lower-to-intermediate ligand densities (~0.001-0.05 ligands nm⁻²) and broader spatial ligand separation, more frequently engage caveolin-mediated endocytosis (CvME) within cholesterol-rich membrane domains, facilitating intracellular delivery while reducing lysosomal exposure. Beyond size and ligand density, nanoparticle shape, ligand spacing (~10-30 nm inter-ligand distance), and receptor-ligand residence time collectively regulate clustering geometry and pathway stability. Clathrin-mediated uptake supports efficient internalization but often directs cargo toward degradative endo-lysosomal compartments; caveolin-associated entry may preserve the integrity of sensitive therapeutic payloads. Integration of quantitative imaging, computational modeling, and microenvironmental factors enables predictive control over intracellular trafficking. These insights establish receptor nano-clustering as a tunable design variable for optimizing therapeutic delivery and achieving pathway-selective enhancement of anti-cancer nanomedicines.