Using Microfluidics to study the Vascular System in a freshman class

Abstract Vascular blood flow provides a unique opportunity to introduce microfluidics in biomedical engineering courses, allowing both experimentation and numerical modeling. Microfluidic-based flow networks can be used to illustrate fluid flow in the body and directly connect to normal and disease-state physiological function. In an introduction to biomedical engineering class that combines labs with lectures, students visualize flow in a model vascular system using a poly(dimethyl)siloxane (PDMS) microfluidic device consisting of a network of various sized channels. The objective of this experiment is to characterize a simple model of the microvascular system using a PDMS microchip. This chip is made using photolithography and simple microfabrication techniques. Students measure flow velocities of micrometer-sized beads within the model network before and after blocking one of the channels and track the redistribution of flow when a channel is occluded. Using a MatLab simulation, students then calculate the resistance of the overall network as well as pressure and velocity in each channel before and after the blockage. These are then compared to experimentally measured velocities and network resistance. This exercise allows students to visualize and model what happens to microvessels when blocked and how the surrounding vessels compensate and redirect flow. The use of a PDMS chip allows for reproducible and easily visualized results without the need for an animal model. Students learn microfluidics, image acquisition and analysis, microfabrication, and MatLab simulations as well as gain an appreciation of the fluid dynamics of microvascular blood flow in health and disease.