(165s) Effective Coverage Characterization of Surface-Immobilized Elastin-like Peptides (ELP) for Electrochemical Applications in Varying Conditions

Polypeptide engineering allows for a high degree of control at the molecular level, and thus has emerged as a promising tool for surface modification. Solid surface immobilized elastin-like polypeptides (ELPs), known for their stimuli-responsive phase transition behavior, have recently gained attention due to their potential applications in electrochemical sensing as well as bio-enabled electrode assembly. The key to the success of these applications is understanding how ELPs can impact the access of redox species and subsequent electron transfer to the metal electrode (so called effective surface coverage). In this study, a series of short ELPs were designed for gold electrode attachment. The gold-surface assembly process was investigated through quartz-crystal microbalance with dissipation (QCM-D) measurements. The ELPs’ impact on the ability of a redox probe accessing a gold surface was characterized via cyclic voltammetry (CV). ELPs were designed with varying guest residues and sequence length, their reactions to solution environment, such as salt concentration, pH, and temperature, were also investigated. Based on the results, a quantitative model describing the relationship between ELP effective surface coverage as a function of the mean hydrophobicity and mass loading was elucidated, illustrating the ability to precisely control surface properties by tuning the ELP sequence. Our study can be used to instruct the design of surface-bound ELP sequences that exhibit desired effective surface coverage for electrochemical applications which interface with biological media.