Lower back pain is the leading cause of physical disability worldwide. In the United States, annual costs associated with lower back pain exceed $100 billion, as 70%-80% of Americans experience debilitating back pain at least once in their lifespan, limiting quality of life and ability to work. Disc degeneration is a major incurable cause of back pain often brought on or exacerbated by excessive loading of the spine. To enable the development of treatments for disc degeneration, more physiological relevant models which include the harsh mechanical environment of the human disc are needed. The dissertation research focused on the Annulus-on-a-Chip (AoC) design, fabrication, and testing of primary cells experimentally and computationally to replicate harsh strains in the annulus fibrosis of the human disc. Strains proved to be controllable, multidirectional, and uniform with magnitudes ranging from -10% in compression to 12% in tension in the axial, radial, and circumferential directions. The dissertation is the first of its kind to replicate complex mechanical loading on a microscale. The Annulus-on-a-Chip was designed to be reconfigurable for other uses such as the modeling of cardiovascular vessels, lymphatic vessels, and the cervix.

Due to the COVID-19 pandemic, the dissertation includes design for pandemic response to help rapidly address the inadequate supply of personal protective equipment (PPE). During the pandemic, shortages of PPE in rural and low-income healthcare settings were thrust into an international bidding war for N95 respirators due to global supply chain disruptions. To extend stockpiles of N95 respirators, benchtop devices for treating N95 respirators with Ultraviolet-C (UVC) germicidal light uniformly, rapidly, and inexpensively were developed and tested. Design iterations improved user safety, efficacy, and process flow, resulting in a set of open-source designs.

Finally, the lessons learned while targeting improvements to societal healthcare through engineering design of the AoC and pandemic response devices led to the ideating, proposing, and implementing of the College of Engineering Business Minor for Engineering PhDs. Intended to complement the strengths specific to PhDs at UC Berkeley, the Engineering Business Minor was designed to significantly support the many students looking to make an impact with their research.