Electrochemical characterization of the stimuli-response of surface-immobilized elastin-like polymers
Electrochemical characterization of the stimuli-response of surface-immobilized elastin-like polymers
复制标题
表面固定弹性蛋白类聚合物刺激响应的电化学表征
DOI：
10.1039/c9sm01681c
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发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Halpern, Jeffrey Mark
中科院分区：
文献类型：
--
作者：
Morales, Marissa A.;Paiva, Wynter A.;Marvin, Laura;Balog, Eva Rose;Halpern, Jeffrey Mark
类弹性蛋白聚合物 (ELP) 由于其刺激响应特性而经常用于各种生物工程应用。高于其转变温度，ELP 将采用不同的结构，促进分子内和分子间的疏水接触，以尽量减少与水环境的不利相互作用。我们用电化学方法表征了表面固定 ELP 的刺激响应行为，对应于两种提议的状态：扩展和塌陷。在延伸状态下，ELP 的溶剂化程度更高。在通过引入环境刺激触发的塌缩状态下，ELP 内的非极性分子内接触受到青睐，从而导致使用电化学阻抗谱 (EIS) 表征的表面可量化的形态变化。将 ELP 修饰电极暴露于高盐浓度环境 (3.0 M NaCl) 后，电荷转移电阻（阻抗的一个组成部分）显示出增加。电荷转移电阻的增加表明电极表面绝缘层的增加，这与所提出的塌陷机制一致，因为 ELP 发生了形态变化，阻碍了氧化还原对交换的动力学。表面固定 ELP 的进一步表征显示出可重复的表面修饰，以及刺激响应的可逆性和可调性。
Elastin-like polymers (ELPs) are frequently used in a variety of bioengineering applications because of their stimuli-responsive properties. Above their transition temperature, ELPs will adopt different structures that promote intra- and intermolecular hydrophobic contacts to minimize unfavorable interactions with an aqueous environment. We electrochemically characterize the stimuli-responsive behavior of surface-immobilized ELPs corresponding to two proposed states: extended and collapsed. In the extended state the ELPs are more solvated. In the collapsed state, triggered by introducing an environmental stimulus, non-polar intramolecular contacts within ELPs are favored, resulting in quantifiable morphological changes on the surface characterized using electrochemical impedance spectroscopy (EIS). Charge transfer resistance, a component of impedance, was shown to increase after exposing an ELP modified electrode to a high salt concentration environment (3.0 M NaCl). An increase in charge transfer resistance indicates an increase in the insulating layer on the electrode surface consistent with the proposed mechanism of collapse, as the ELPs have undergone morphological changes to hinder the kinetics of the redox couple exchange. Further characterization of the surface-immobilized ELPs showed a reproducible surface modification, as well as reversibility and tunability of the stimuli-response.