Published: Aug. 20, 2017 By

Editor’s Note: This is the first post in an occasional series about CU Boulder students’ summer experiences in engineering. Tell us about your summer experience at

Madeleine Sitton with Genentech signThis summer I am interning in San Francisco at Genentech, a leading biotechnology company that creates drugs to treat serious, life-threatening illnesses.

I work as an engineer in the purification pilot plant, which is part of the Pharma Technical Development division. After researchers identify a drug they want to make, the Pharma Technical Development team takes over to figure out how to make that drug. The manufacturing process is modeled in two pilot plants, which are scaled-up versions of cell culture and purification processes done in the lab, so that engineers can work out the kinks of the proposed process before sending it out to manufacturing plants.

In the cell culture pilot plant, DNA that expresses the desired protein is transfected into cells, which are then grown up in large bioreactors. After enough cells have been grown, they are passed on to the purification pilot plant. We harvest the desired protein that the cells have been producing and use several chromatography and filtration steps to isolate it. We then pass the drug along the chain to other researchers and engineers, who finish fine-tuning the drug so it can be ready for the first clinical trials.

What excites me most about this experience is being able to apply many of the engineering concepts that I learned in fluid dynamics, separations and biokinetics to my daily work. Being able to see and work with so many of the things that I learned about in textbooks and lectures has been an invaluable learning experience.

Madeleine Sitton at Golden Gate BridgeWorking for Genentech has not only further confirmed my desire to pursue a PhD after graduation but has also shown me the benefits of working in industry. In industry, I am able to work on novel therapies that target diseases that have few to no treatments, like Alzheimer’s or cancer. In my role, I am able to physically work with drugs that can change so many people’s lives for the better. It is exciting and fulfilling work that has made this summer at Genentech incredibly rewarding.

Please feel free to reach out to me at if you have any questions about Genentech, research or chemical and biological engineering in general.

Maddie Sitton is a rising senior in chemical and biological engineering.