Arntzen studies plant-derived pharmaceuticals and vaccines in collaboration with faculty, government researchers, and industrial product development groups. He has used both transgenic and viral vector approaches to move genes into plant cells. His initial efforts focused on traits that improved crop production, which led him toward manufacturing protein pharmaceuticals in plant leaves. He and his collaborators pioneered subunit vaccine production and formulation.

In 2015, Arntzen was chosen as the No. 1 honoree among Fast Company’s annual “100 Most Creative People in Business” for his leadership role in developing ZMapp, a therapeutic produced in tobacco to fight Ebola.

ZMapp is a serum made in a plant with a notorious reputation as a killer, tobacco. The pathway from discovery to treatment began with an idea Arntzen had to produce low-cost vaccines in plants to fight devastating infectious diseases in the developing world. Then, after 9/11 and the anthrax attack on the U.S. Senate, the government invested heavily in biodefense, including $3.7 million to Arntzen and a small San Diego-based startup led by Larry Zeitlin and Kevin Whaley, Mapp Biopharmaceutical. The goal was to develop plant-based defenses against pathogens, including Ebola, that could be used as potential biological threats. With a dream team of collaborators, they modified the tobacco plants to produce a protective cocktail made of three monoclonal antibodies. This therapeutic cocktail proved to be 100 percent effective in protecting animals against Ebola, even five days after exposure. 

Currently, Arntzen uses his experience in plant biotechnology in order to advise the National Academy of Sciences, other government agencies, and corporate entities on the strategic useof new technology in agriculture and human health programs. Though he isn't expanding his research team at ASU, he serves in an adminstrative advisory role at Biodesign and continues to grow his industrial and government collaborations to support multi-disciplinary academic research teams.