Protein Adsorption to Thermally Responsive Surfaces

The ability to control the interactions between biological components and synthetic interfaces has received much attention in the past few decades. In order to modify interfacial interactions, a promising method is to coat surfaces or interfaces with stimuli responsive coatings. Such switchable coatings can be used to manipulate specific biological responses such as adsorption/desorption of proteins. Protein adsorption is an intricate phenomenon as the structure and, thereby the function of proteins, changes upon adsorption. In order to understand this mechanism, we have performed surface modification with one of the most studied thermally responsive polymer, poly (N-isopropylacrylamide) (PNIPAAm) which exhibits a hydrophilic/hydrophobic transition at a critical temperature of 32⁰C in aqueous solutions. We have investigated immunoglobulin-G (IgG) adsorption on PNIPAAm coated surfaces. In order to characterize the dynamics and conformational changes of the adsorbed protein layer, we have employed quartz crystal microbalance with dissipation (QCM-D) and dual ellipsometry-fluorescence techniques.