A Modular, High Throughput Microfluidic Platform to Study the Effects of 3D Cell Culture on Endothelial Function

Abstract

Knowledge of the signaling effects of the microenvironment on endothelial cell function is critical for the understanding of cardiovascular disease development and progression. Currently, microfluidics is the gold standard in vitro platform for the study of endothelial cells due to the inclusion of shear stress in the model. However, these models predominantly culture cells on a traditional flat surface. To build a more complete biomimetic model, the cell culture surface should emulate the basement membrane (BM) of a blood vessel, characterized as an array of aligned microfibers. Therefore, to bridge this gap in technology, a highly customizable microfluidic system was developed with the ability to easily integrate 3D scaffolds into the model. To demonstrate the usefulness of this system, a 4.88-fold increase in nitric oxide (NO) production was observed in cells cultured on a 3D scaffold as opposed to a conventional 2D surface. This system was then modified to incorporate trans endothelial/epithelial resistance (TEER) measurements into the model, allowing for the investigation of chemical effects on barrier integrity in near real-time. Traditionally, TEER instruments are very expensive and rigid in construction, which complicates experimental design. Using an Arduino microcontroller and a pair of metal leads, a cheap customizable TEER meter was developed and implemented into the microfluidic system. Using this system, the effect of doxorubicin, a common anticancer drug, on endothelial cell barrier integrity was monitored in near real-time for a period of 24 hours. Finally, this microfluidic platform was utilized to observe a previously unknown signaling effect of surface architecture on endothelial cell function. The surface-dependent expression of beta-1 integrin was correlated to an increase of phosphorylation of the endothelial nitric oxide synthase (eNOS), which results in an increase in NO production. This microfluidic platform was shown to be a powerful tool for pre-clinical biological research and will broadly benefit the biotechnology field.