Confinement of proteins at the porous chromatographic support leads to anomalous confined diffusion. Molecular level understanding and control over such complex dynamics are needed for predictive applications. Cross-linked hydrogels made of stimuli-responsive polymers provide unique control over their physio-chemical properties by spatial and chemical transformation with environmental changes. These stimuli-driven transformations generate a dynamic heterogeneity of hydrogels’ physio-chemical properties and are the driving forces behind their underlying surface chemistry. Characterizing Nanoscale structure and dynamics at crowded environments under ambient conditions is challenging with traditional techniques, such as AFM. Fluorescence correlation spectroscopy combined with Super-resolution Optical Fluctuation Imaging (fcsSOFI) is ideal to understand the complex dynamic behavior of proteins and characterize porous polymer surface. Herein, we use fcsSOFI and single particle tracking to understand the dynamics of a model protein lysozyme on the dual stimuli-responsive (pH and temperature) hydrogel surface and inside the hydrogel pores. Lysozyme shows variable reversible surface dynamics on the poly-N isopropylacrylamide hydrogel surface and nanopores. Also, chemical heterogeneity of the surface and geometrical confinement dictates the dynamic hoping behavior of proteins at the complex nanogel surfaces. The single molecule picture of these complex processes and active control of protein dynamics will inspire better bottom-up design strategies with other stimuli-responsive polymers for various applications including, but not limited to, separation science and biomedical sciences.

Superresolution (fcsSOFI) imaging of porous polymer support and active control of protein dynamics

2019 Fall National Meeting

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