Understanding the Phase Behavior of a Multi-Stimuli-Responsive Elastin-Like Polymer: Insights from Dynamic Light Scattering Analysis

Elastin-like polymers are a class of stimuli-responsive protein polymers that hold immense promise in applications such as drug delivery, hydrogels, and biosensors. Yet, understanding the intricate interplay of factors influencing their stimuli-responsive behavior remains a challenging frontier. Using temperature-controlled dynamic light scattering and zeta potential measurements, we investigate the interactions between buffer, pH, salt, water, and protein using an elastin-like polymer containing ionizable Lysine residues. We observed the elevation of transition temperature in the presence of the common buffering agent HEPES at low concentrations, suggesting a “salting-in” effect of HEPES as a co-solute through weak association with the protein. Our findings motivate a more comprehensive investigation of the influence of buffer and other co-solute molecules on elastin-like polymer behavior.