Composition-Dependent Chemical Environments of Charged Polymer Condensates

In this project, Professor Jennifer E. Laaser of the University of Pittsburgh will investigate how polymer composition impacts chemical transport and reactivity in “protein-like” polymer condensates. In cells, biological condensates play a critical role in organizing and controlling important biochemical reactions. This project will help scientists understand how to design materials that mimic these environments, which will in turn inform development of new ways to synthesize important biologically-derived chemicals and pharmaceuticals. In parallel with these research efforts, this project will also support development of the scientific workforce through outreach to local high school students, training of graduate and undergraduate student researchers, and development of a new laboratory curriculum offering second-year college students authentic research experiences in polymer synthesis and characterization. Polyacrylamide-based polyampholytes with mixtures of charged, hydrophilic, hydrophobic, and aromatic sidechains will be synthesized using a PET-RAFT approach recently developed in the PI’s laboratory. Condensates will be prepared under standard buffer conditions, and a suite of fluorescence microscopy and spectroscopic techniques will be used to probe how the polymer composition impacts (1) partitioning of small molecules between the condensate and its environment, (2) the local polarity and heterogeneity of the solvation environment within the condensates, and (3) transport of small molecules within condensates and across their interfaces. This work will advance fundamental understanding of the macromolecular features that determine the physicochemical environments – and thus chemical reactivity – in polymer and protein condensates. This knowledge is in turn expected to drive innovation in development of novel condensate-based droplet reactors capable of mimicking biochemical reactions at scale. Finally, portions of this work will be adapted into a new course-based undergraduate research experience, expanding opportunities for undergraduates at the PI’s university to engage in authentic research opportunities and springboard their STEM careers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.