Sagasti Ariane, Bouropoulos Nikolaos, Kouzoudis Dimitris, Panagiotopoulos Apostolos, Topoglidis Emmanuel, Gutiérrez Jon
BCMaterials, Ibaizabal Bidea, Edificio 500, Parque Tecnológico de Bizkaia, 48160 Derio, Spain.
Department of Materials Science, University of Patras, 26504 Patras, Greece.
Materials (Basel). 2017 Jul 25;10(8):849. doi: 10.3390/ma10080849.
In the present work, a nanostructured ZnO layer was synthesized onto a Metglas magnetoelastic ribbon to immobilize hemoglobin (Hb) on it and study the Hb's electrochemical behavior towards hydrogen peroxide. Hb oxidation by H₂O₂ was monitored simultaneously by two different techniques: Cyclic Voltammetry (CV) and Magnetoelastic Resonance (MR). The Metglas/ZnO/Hb system was simultaneously used as a working electrode for the CV scans and as a magnetoelastic sensor excited by external coils, which drive it to resonance and interrogate it. The ZnO nanoparticles for the ZnO layer were grown hydrothermally and fully characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and photoluminescence (PL). Additionally, the ZnO layer's elastic modulus was measured using a new method, which makes use of the Metglas substrate. For the detection experiments, the electrochemical cell was performed with a glass vial, where the three electrodes (working, counter and reference) were immersed into PBS (Phosphate Buffer Solution) solution and small H₂O₂ drops were added, one at a time. CV scans were taken every 30 s and 5 min after the addition of each drop and meanwhile a magnetoelastic measurement was taken by the external coils. The CV plots reveal direct electrochemical behavior of Hb and display good electrocatalytic response to the reduction of H₂O₂. The measured catalysis currents increase linearly with the H₂O₂ concentration in a wide range of 25-350 μM with a correlation coefficient 0.99. The detection limit is 25-50 μM. Moreover, the Metglas/ZnO/Hb electrode displays rapid response (30 s) to H₂O₂, and exhibits good stability and reproducibility of the measurements. On the other hand, the magnetoelastic measurements show a small linear mass increase versus the H₂O₂ concentration with a slope of 152 ng/μM, which is probably due to H₂O₂ adsorption in ZnO during the electrochemical reaction. No such effects were detected during the control experiment when only PBS solution was present for a long time.
在本工作中，在美特格拉斯磁弹性带上合成了纳米结构的ZnO层，以固定血红蛋白（Hb）并研究Hb对过氧化氢的电化学行为。通过两种不同技术同时监测H₂O₂对Hb的氧化作用：循环伏安法（CV）和磁弹性共振（MR）。美特格拉斯/ZnO/Hb系统同时用作CV扫描的工作电极以及由外部线圈激发的磁弹性传感器，外部线圈驱动其共振并对其进行检测。用于ZnO层的ZnO纳米颗粒通过水热法生长，并通过X射线衍射（XRD）、扫描电子显微镜（SEM）和光致发光（PL）进行了全面表征。此外，使用一种利用美特格拉斯基板的新方法测量了ZnO层的弹性模量。对于检测实验，在玻璃小瓶中进行电化学池实验，将三个电极（工作电极、对电极和参比电极）浸入磷酸盐缓冲溶液（PBS）中，并逐滴加入少量H₂O₂。每次加入一滴后，每隔30秒和5分钟进行一次CV扫描，同时由外部线圈进行磁弹性测量。CV曲线揭示了Hb的直接电化学行为，并显示出对H₂O₂还原的良好电催化响应。在25 - 350 μM的宽范围内，测得的催化电流与H₂O₂浓度呈线性增加，相关系数为0.99。检测限为25 - 50 μM。此外，美特格拉斯/ZnO/Hb电极对H₂O₂显示出快速响应（30秒），并且测量具有良好的稳定性和重现性。另一方面，磁弹性测量显示质量随H₂O₂浓度有小的线性增加，斜率为152 ng/μM，这可能是由于电化学反应过程中H₂O₂在ZnO中的吸附所致。在仅存在PBS溶液的长时间对照实验中未检测到此类影响。
