A Tumor Spheroid Array Chip for High-Fidelity Evaluation of Liposomal Drug Delivery Through the EPR Effect

Abstract

Conventional two-dimensional (2D) culture systems fail to recapitulate the structural and functional complexity of the tumor microenvironment (TME), limiting their translational relevance for preclinical drug evaluation. Here, we present a high-throughput microfluidic Tumor Spheroid Array (TSA)-Chip for investigating nanocarrier-based cancer therapies under physiologically perfusable conditions. Multicellular colorectal tumor spheroids—comprising cancer cells, endothelial cells, and fibroblasts—were embedded in a fibrin hydrogel to facilitate the formation of peritumoral vascular networks. The TSA-Chip enables continuous medium perfusion, live imaging, and quantitative assessment of vascular permeability. Using this platform, we evaluated the delivery and therapeutic efficacy of liposomal 5-fluorouracil (5-FU), leveraging the enhanced permeability and retention (EPR) effect. Compared to free 5-FU, the liposomal formulation showed improved tumor-specific accumulation and reduced vascular leakage. Furthermore, combination treatment with the anti-angiogenic agent Cyramza™ (ramucirumab) enhanced tumor suppression while preserving vascular integrity. This scalable and physiologically relevant platform provides a robust preclinical model for assessing nanoparticle transport and therapeutic outcomes in a perfusable TME, advancing precision oncology research.