(3o) Poly- and Perfluoroalkyl Substances (PFAS) Bind to Proteins and Stiffen Membranes: Using Physicochemical Properties to Characterize Human and Environmental Effects

Poly- and perfluoroalkyl substances (PFAS) are a class of synthetic compounds that have been linked to negative impacts on human health. To fully understand their effects, our work has focused on the fate and transport of PFASs within the human body. This approach focuses on partitioning into both protein phases and lipid phases, including cell membranes. The association with serum albumin serves as a marker for PFAS exposure as well as a mechanism for transport throughout the body. Thus, binding to both human and bovine serum albumins was studied over a range of PFAS chain lengths and head groups via fluorescence spectroscopy and equilibrium dialysis. These results were compared to thermodynamic data with the use of isothermal titration calorimetry and differential scanning calorimetry to observe trends in PFAS binding. We chose a range of legacy and emerging PFAS, including an aqueous film forming foam (AFFF) sample, to compare physicochemical properties (ie octanol-water partitioning coefficient, acid dissociation constant, etc) with protein binding affinity. This approach allows for translation of our research to other emerging compounds of interest.

Not only does protein binding enhance the effect of PFASs on the body but so too does their association with lipids, specifically incorporation into cell membranes. Previous work in this area has focused on synthetic liposomes, indicating that PFAS induce membrane leakage. We observed an unexpected stiffening of the membrane upon addition of PFAS to Alcanivorax Borkumensis, a marine bacterium associated with biodegradation of oil spills. The PFASs did not, however, cause a delay in the growth of a. borkumensis when assessed by the comparison of growth curves in the absence and presence of environmentally relevant concentrations of different PFASs. Overall, this work investigates a range of PFAS properties and their effects on both protein and lipid association.

Teaching Interests

My primary focus for my future career is in teaching chemical engineering and developing new techniques and tools to teach engineering effectively. My teaching assistant experiences so far have allowed me to assist in creating lesson plans, course materials, and exams as well as teaching up to 10 classes per semester. I found that I enjoy teaching senior level chemical engineering separations courses, where students must put all they have learned together to solve engineering problems. I also recognize this requires a solid foundation in chemical engineering fundamentals so I am interested in researching the best ways to create that foundation.