Pennathur began teaching at UCSB in the Mechanical Engineering department in July 2007. Her research group focuses on using fundamental fluidics knowledge at both micro- and nano -scales to create novel devices for practical applications. Major efforts include creating and developing enabling tools to identify and characterize biological substances, improving current bionalaytical devices, and designing/engineering entire systems for point-of-care usage. Prior to coming to UCSB, Pennathur taught at University of Twente. She has held multiple positions at various companies and schools such as: Sandia National Laboratories, Stanford University, National Institute of Standards and Technology, Tigris Corporation, and Lockheed Martin.