Numerical investigation of drug transport from blood vessels to tumor tissue using a Tumor-Vasculature-on-a-Chip

The delivery of adequate concentration of anticancer drugs to tumor site is critical to achieve effective therapeutic treatment, but it is challenging to experimentally observe drug transport and investigate the spatial distribution of the drug in tumor microenvironment. In this study, we investigated the drug transport from a blood vessel to tumor tissue, and explored the effect of tumor size, tumor numbers and positioning on drug concentration distribution using a numerical method in combination with a microfluidic Tumor-Vasculature-on-a-Chip (TVOC) model. The TVOC model is composed of a vessel channel, a tumor channel sandwiched with a porous membrane. A species transport model based on computational fluid dynamics was adapted to investigate drug transport. The numerical simulation was firstly validated using experimental data, and then used to analyse the spatial-temporal structure of the flow, and to investigate the effect of tumor size and positioning on drug transport and drug concentration heterogeneity. We found the drug concentration surrounding the tumor is highly heterogeneous, with the most downstream point the most difficult for drugs to transport and the nearest point to the blood vessel the easiest. Moreover, tumor size and positioning contribute significantly to this drug concentration heterogeneity on tumor surface, which is dramatically augmented in large and downstream-positioned tumors. These studies established the relationship between solid tumor size/positioning and drug concentration heterogeneity in the tumor microenvironment, which could help to understand heterogenous drug distribution in tumor microenvironment