Discovering the impact of varying viscosity on the volume dispensed in a microfluidic airway-on-a-chip device
Henry Shi
Collingwood School
Floor Location : M 081 N

In the past few years, the research & development cost for drug discovery has risen all around the world. For example, in the United States, a 2014 article stated that 8 in 10 medicinal projects are abandoned, and that the average cost for one successful drug has increased by almost 2.5x since 2003. Currently, drug targeting mainly fails due to human complexity, which creates intangible problems and causes most models (such as popular static well cultures and animal models) to become unrealistic. Without impactful drug efficacy, diseases are negatively affecting many peoples’ lives and increasing the burden to healthcare systems all around the world. For example, Chronic Obstructive Pulmonary Disease (COPD), a common inflammatory disorder of the lung characterized by airflow limitation, has been diagnosed for 2.6 million people in Canada alone, responsible for $12 billion/year in direct health care expenditures. There are currently no effective therapeutic treatments for this prevalent disease all around the world.

Microfluidic technology (e.g. lung-on-a-chip) can potentially be applied to solve this problem. The goal of this technology is to imitate a functional interface present in the human lung/small airway by growing/culturing cells from patients in the device, so that the chip’s reactions to researchers’ experimentation would be realistic and similar to what a real patient lung would do. Furthermore, researchers can flow smoke through and observe the impacts on the cells grown inside, instead of relying on results from inaccurate mouse models. It is anticipated that this technology can reduce failed experiments, and lead to higher rates of success in drug discovery.

Researchers at The University of British Columbia (UBC) have started to develop an airway-on-a-chip device. Their aim is to create a working, accurate, and relatively price-effective chip that imitates the human small airway. Many factors have been tested to ensure the model's effectiveness, such as mechanical properties, fabrication quality, cell culture quality, and general similarity to a human biological lung/small airway. After each test, new iterations of the design were generated based on troubleshooting results to optimize the chip.

Last summer, over a 2-month period I shadowed the UBC team in the fabrication process and some preliminary experiments. As the team continues their research and optimization of the design, I plan to investigate how the viscosity of a solution and flow rate of the syringe pump (used to pump fluids through the chip) can affect final volume flown through. Within the lungs various fluids/substrates come in contact with the cells such as blood, air and mucus. Due to the wide range of viscosities it is important to ensure the system controlling the delivery of these to the chip (the syringe pump) maintains its flow rate accurately. If that is not possible because of reasons such as high viscosity, it is necessary to be aware of these limitations, and for potential calibration steps to compensate for any offset in order to deliver fluidic substances at precise volumes