(337k) Monitoring Inconsistent ELP Surface Modification By Thiol Desorption

Elastin-like polymers (ELPs) have gained attention recently for their potential as a transduction enhancement for surfaces. However, consistent surface modification is required to ensure a consistent response model. Gold surfaces with ELP has been a challenge in practice, but can be achieved with careful modification procedure, keeping variables such as temperature, ELP concentration, time of modification, and dissolution procedure consistent. We hypothesize that further ELP surface modification inconsistencies are due to ELP that physiosorbs to the gold surface instead of forming new chemisorption modification sites. This presentation will share data demonstrating that inconsistencies in electrochemical measurements of surface-bound ELP are due to inconsistent physisorption of non-chemisorbed ELP molecules. Cyclic voltammetry in KOH was applied to surface-bound ELP at different ELP concentrations in order to reduce the ELP - gold thiol surface. The area under the reduction peak is equal to amount of ELP directly bound to the surface. Electrochemical impedance spectroscopy (EIS) was used with a Randles circuit model to determine the charge transfer resistance of the surfaces. By comparing the trend of charge transfer resistance to surface-bound ELP, we show that optimization coverage points for ELP modified surfaces.