Acetylcholinesterase Adsorption on Modified Gold: Effect of Surface Chemistry on Enzyme Binding and Activity
Acetylcholinesterase Adsorption on Modified Gold: Effect of Surface Chemistry on Enzyme Binding and Activity
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DOI：
10.1021/acs.langmuir.3c00648
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发表时间：
2023-07-13
期刊：
影响因子：
3.9
通讯作者：
Webb，Lauren J.
中科院分区：
文献类型：
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作者：
Correira，Joshua M.;Madeksho，Diane E.;Webb，Lauren J.
表面化学在生物传感器和生物催化剂的性能中起着至关重要的作用，其中酶直接与固体载体相互作用。在这项工作中，我们研究了表面电荷和疏水性对乙酰胆碱酯酶（AChE）直接吸附到改性金表面的结合和活性的影响。表面修饰包括以不同摩尔%的−COO-、−NH3+、−OH和− CH 3官能团封端的自组装单分子膜（SAM）。我们还研究了带正电荷和负电荷的螺旋肽共价偶联到SAM的影响。使用椭圆偏振光谱法，我们测量了表面浓度的乙酰胆碱酯酶在每个改性表面吸附1小时后。我们发现表面浓度与表面疏水性成正比（r= 0.76）。在更疏水的表面上观察到最高的结合。我们还使用比色法测量了每个表面上AChE的比活性，发现活性与表面疏水性成反比（r=-0.71）。在更亲水的表面上观察到最高的活性。绘制比活性与表面浓度的关系图显示了类似的关系，在低AChE密度（单层的约20%）下观察到最高活性，表面以50% − COO-或−NH3+和50% − CH 3官能团终止。有趣的是，这是类似的疏水性与亲水性氨基酸残基的表面上的乙酰胆碱酯酶的近似组成。这些表面也表现出最高的总活性：由于适度结合和高活性保留的组合，与裸金相比，活性提高了100%。这项工作强调了开发新的附着策略的重要性，这些策略超越了直接吸附，可以促进，调节和优化高结合和高活性保留。
Surface chemistry plays a crucial role in the performance of biosensors and biocatalysts, where enzymes directly interact with a solid support. In this work, we investigated the effect of surface charge and hydrophobicity on the binding and activity of acetylcholinesterase (AChE) following direct adsorption to modified gold surfaces. Surface modifications included self-assembled monolayers (SAMs) terminated with −COO–, −NH3+, −OH, and −CH3functional groups at varying mole %. We also investigated the effects of positively and negatively charged helical peptides covalently coupled to the SAM. Using spectroscopic ellipsometry, we measured the surface concentration of AChE on each modified surface after 1 h of adsorption. We found that surface concentration was directly proportional to surface hydrophobicity (r= 0.76). The highest binding was observed on the more hydrophobic surfaces. We also measured the specific activity of AChE on each surface using a colorimetric assay and found that activity was inversely proportional to surface hydrophobicity (r= −0.71). The highest activity was observed on the more hydrophilic surfaces. Plotting specific activity versus surface concentration showed a similar relationship, with the highest activity observed at low AChE densities (∼20% of a monolayer) on surfaces terminated with 50% −COO–or −NH3+and 50% −CH3functional groups. Interestingly, this is similar to the approximate composition of hydrophobic versus hydrophilic amino acid residues on the surface of AChE. These surfaces also exhibited the highest total activity: a ∼100% improvement over bare gold due to a combination of moderate binding and high activity retention. This work highlights the importance of developing new attachment strategies beyond direct adsorption that promote, tune, and optimize both high binding and high activity retention.