Study On Biofluid Mechanics Of Tumor Drug Binding In The Microcirculation Flow

Cancer is one of the leading killers of human being. Liposome as a carrier of anti-tumor angiogenesis drug has become one of the frontier research topics in cancer therapies, especially for the receptor-ligand mediated liposome delivery.In this study, our attentions are focused on effects of the shear rate of tumor blood flows on the binding efficiency of liposomes to tumor vascular endothelial cells. A flow-chamber experimental system is set up to simulate the flow conditions accordingly. Based on the micro-flow system and fluorescence technique, three groups of experiments, that is, pre-experiments, washout experiments and binding experiments, are carried out. The experimental data on binding and uptake efficiency of the non-targeting / targeting liposomes to the targeted cells are collected and analyzed in order to provide scientific basis for drug delivery and cells binding in vivo flow environments.The results reveal that, the shear rate has great effects on both binding and uptake of the liposomes. The washout experiments show that:(1) the adhesion force of non-targeting liposomes binding to the endothelial cells is much weaker than that of targeting liposomes;(2) the shear rate threshold of the bounded targeting liposomes washed out from the endothelial cells is much higher than that of the non-targeting liposomes;(3) the uptake timescale of targeting liposomes is much less than that of the non-targeting liposomes. From the binding experiments, it is found that:(1) the influence of the shear rate on the targeting liposomes binding is very great compared with that on the non-targeting liposomes binding, which is consistent with our pre-experiment results;(2) in a certain range of the shear rate, the flow conditions may promote the binding efficiency of the targeting liposomes;(3) the forces of the targeting liposomes binding to the endothelial cells are much stronger than those of the non-targeting liposomes.To further explore hemodynamic problems in the blood flows and predict unsteady dynamical behaviors of multiple cells in the flows, we present a simple model using the potential flow theory to describe multiple moving objects under fully hydrodynamic interactions, and get some important conclusions.