Environmental Stimuli of Amphiphilic Block Copolymer Assemblies

Student’s name: Stephanie Avalos-Padilla Home Institution: Mesa Community College NNCI Site: NCI SW @ Northern Arizona University REU Principal Investigator: Dr. Gabriel A. Montaño REU Mentor: Alexis Alcala Abstract: Poly(butadiene)-block-poly(acrylic acid) (pAA) and Poly(butadiene)-block-poly(ethylene oxide) (pEo) are block copolymers that are dynamic, robust, and can form membranes similar to those seen in nature. Like lipids, they possess an amphiphilic structure- meaning they both have a hydrophobic and a hydrophilic side. This study focuses on how micelles made from these two polymers react to pH and ionic strength during their formation to be able to better understand cell membrane structure. Methods used include Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), Ultraviolet Visualization (UV-Vis), and Fluorescence Recovery After Photobleaching (FRAP)- which in order, measured 2D membrane thickness, micelle size, wavelength excitation, and membrane fluidity. We are anticipating trends between high pH and larger size, more concentrated ions and larger size, as well as stronger fluidity in pAA compared to pEo. By studying the environmental stimuli that impact synthetic membrane structures, we hope to better understand how cell membranes can sense, respond, and adapt to changing environments. In the future, we hope this research on how these polymers react to these stimuli can allow us to use them in various industries such as using them in precise drug delivery, as a form of biosensors, and other biocompatible applications.