磁性印迹纳米粒子固定血红蛋白修饰磁性电极构建过氧化氢传感器

采用表面印迹技术，以磁性二氧化硅纳米粒子（Fe₃O₄@SiO₂ NPs）作为载体、血红蛋白（Hb）为模板分子、正硅酸乙酯（TEOS）为印迹聚合物单体，制备了Hb印迹Fe₃O₄@SiO₂的磁性印迹纳米粒子（MMIPs NPs）. MMIPs NPs具有磁性内核和血红蛋白印迹壳层的核壳结构，可以富集并固定Hb. 使用壳聚糖将MMIPs NPs固定于磁性电极表面，构建血红蛋白类酶生物传感器，研究了Hb对过氧化氢（H₂O₂）的催化活性. MMIPS NPS相比于磁性非印迹纳米粒子（MNIPS NPS），催化电流增加了14.3%. 采用磁性电极，MMIPS NPS、Hb和O₂的顺磁性使得该类酶生物传感器对H₂O₂的催化电流增加了60.0%. 血红蛋白类酶生物传感器电流响应与H₂O₂浓度在25 ~ 200 μmol·L^-1间呈线性关系，检出限为3 μmol·L^-1（S/N=3），表明该类酶传感器对H₂O₂具有良好的催化性能.

Electrochemical Sensor Based on Magnetic Electrode Modified with Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin for Determination of Hydrogen Peroxide

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using Fe₃O₄@SiO₂ NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic Fe₃O₄ NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor to catalyze the reduction of hydrogen peroxide (H₂O₂). Compared with magnetic non-imprinted polymer nanoparticles (MNIPs NPs), the MMIPs NPs biosensor enhanced the response by 14.3%. Notably, an introduction of a magnetic field made the biosensor more sensitive owing to the paramagnetism of MNIPs NPs, Hb and O₂ molecules. The reduction current of H₂O₂ on Hb/MMIPs NPs modified magnetic glassy carbon electrode increased by 60.0%. Under the optimum condition, the linear detection range of H₂O₂ was 25 ~ 200 μmol·L^-1 with the detection limit of 3 μmol·L^-1 (S/N = 3), which showed that Hb enzyme-like biosensor had a good catalytic performance for H₂O₂.