Quantification of the Effects of Hydrophobicity and Mass Loading on the Effective Coverage of Surface-Immobilized Elastin-like Peptides

Elastin-like peptides (ELPs) immobilized to solid surfaces have recently gained attention for use in electrochemical applications in sensing as well as bioenabled electrode assembly. Key to the success of these applications is understanding how ELPs impact the access and electron transfer of reacting species to the solid surface (effective surface coverage). In this study, ELPs with varying hydrophobicity and sequence length were designed for gold attachment and the effect on the ability of a redox probe to access a gold surface was characterized by cyclic voltammetry. A quantitative model describing the relationship between ELP effective surface coverage as a function of mean hydrophobicity and mass loading was elucidated based on the results, showing the ability to precisely control surface properties by tuning the ELP sequence. Deviations from the model were associated with guest residue charge. This model will be useful for the design of surface-bound ELP sequences that exhibit desired effective surface coverage for electrochemical as well as biomaterial applications.

固定于固相表面的弹性蛋白样肽（Elastin-like peptides, ELPs）近年来在传感电化学应用以及生物赋能电极组装领域受到广泛关注。此类应用取得成功的核心在于阐明ELPs如何影响反应物种抵达固相表面的路径与电子传递过程，即有效表面覆盖度（effective surface coverage）。本研究设计了一系列具有不同疏水性与序列长度的ELPs以实现金表面固定，并通过循环伏安法（cyclic voltammetry）表征了氧化还原探针（redox probe）抵达金表面的能力受ELPs影响的效应。基于实验结果，本研究构建了定量模型，该模型描述了ELP有效表面覆盖度与平均疏水性及质量负载量之间的函数关系，证实可通过调控ELP序列精准调控表面性质。模型与实验结果的偏差则与可变残基（guest residue）的电荷相关。该模型可用于设计具备目标有效表面覆盖度的固相固定ELP序列，助力电化学与生物材料领域的相关应用。