组成图示
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传感器类型
电化学生物传感器
检测对象
叔丁基过氧化氢（tert-butyl hydroperoxide, TBHP）；身体乳（body lotion）中有机过氧化物（organic peroxides）。样品基质：含0.1 M TBAP的THF、DMF、DMSO、乙酸乙酯、二氯甲烷、乙腈、氯仿等有机溶剂，以及乙酸乙酯提取的身体乳样品。
检测原理
该传感器以血红素-组氨酸/超分子水凝胶作为人工过氧化物酶识别与催化层。TBHP穿过海藻酸钠膜扩散至血红素活性中心，血红素Fe(III)在催化循环中接受电子并促进TBHP还原，电极在-0.6 V下记录到还原电流。超分子水凝胶纳米纤维网络将血红素以单体形式固定，减少二聚，提高直接电子转移和催化效率；海藻酸钠膜保留必要水分，维持人工酶在纯有机溶剂中的活性。随着TBHP浓度增加，电极表面催化还原速率提高，稳态安培电流线性增大。该体系无需外加介质，依靠血红素直接电子转移和模拟酶催化实现信号放大。
检测灵敏度
LOD: 27 μM；线性范围: 6.6 × 10−5–1.27 × 10−2 M；R^2 = 0.9995
效应效果
该电极对TBHP的响应约为游离血红素修饰电极的13倍、HRP修饰电极的3倍，线性范围宽于多数天然酶修饰生物传感器和液相色谱法，检出限低于已有报道。响应时间约10±2 s达到95%稳态电流，快于常见有机相酶电极的约1 min。在1.32 mM TBHP下，10次连续测量RSD为1.1%，5个独立制备电极RSD为3.8%；4℃保存1周仍保持90%初始响应。在身体乳样品中测定约324 μg有机过氧化物，加标回收率为97.9–101.2%，表明基质干扰小。作者认为其可在亲水和疏水溶剂中免缓冲液/介质使用，适用于化妆品等实际样品中有机过氧化物检测。
传感器的构成
- 基底/工作电极：玻璃碳电极（GCE），抛光后作为电子转导基底
- 纳米材料修饰层：Fmoc-L-赖氨酸（FLlys）/Fmoc-L-苯丙氨酸（FLphe）自组装超分子水凝胶（supramolecular hydrogel）纳米纤维网络，作为载体固定血红素
- 识别/催化元件：血红素（hemin）与组氨酸（histidine）形成人工过氧化物酶，催化TBHP还原
- 信号换能层：血红素Fe(III)/Fe(II)氧化还原对，直接电子转移产生安培电流
- 保护/保水膜：海藻酸钠（sodium alginate, SA），覆盖人工酶层，保持水分、防止泄漏并允许TBHP扩散
- 支持电解质：四丁基高氯酸铵（TBAP，0.1 M），在有机溶剂中提供离子导电
- 三电极系统：Ag/AgCl（饱和KCl）参考电极与Ag丝对电极，完成电位测量和电流回路
中文摘要
基于两亲性寡肽自组装形成的超分子水凝胶与血红素混合所形成的新型人工酶，作者制备了一种有机相人工酶电极：将人工酶涂覆于玻璃碳电极表面，再用海藻酸钠覆盖保护。扫描电镜显示超分子水凝胶在电极表面保持纳米纤维结构。血红素以单体形式分散于超分子水凝胶中，显著促进其在有机溶剂中的直接电化学行为。与主要呈二聚体的游离血红素修饰电极相比，该电极对叔丁基过氧化氢（TBHP）具有更高的电催化能力。采用安培法可检测低至27 μM的TBHP，线性范围为6.6×10−5至1.27×10−2 M。传感器约10±2 s即可达到95%稳态电流。更重要的是，该电极无需额外添加缓冲液或介质，即可在亲水和疏水有机溶剂中应用，有利于拓展有机相酶电极对不同溶解性底物的检测。该人工酶电极已成功用于身体乳样品中有机过氧化物的测定。
英文摘要
Based on the newly discovered artificial enzyme formed by mixing hemin with supramolecular hydrogels via the self-assembly of amphiphilic oligopeptides, we prepared a novel organic phase artificial enzyme electrode by coating the artificial enzyme on an electrode which was then covered with sodium alginate for protection. Scanning electron micrograph showed that the supramolecular hydrogel kept its nanofibers structure on the electrode surface. Hemin dispersed in the supermolecular hydrogel as monomer greatly promotes its direct electrochemistry behavior in organic solvents. At the same time, this electrode exhibited higher electrocatalytic ability to tert-butyl hydroperoxide (TBHP) than free hemin modified electrode (free hemin mainly present as dimer). As low as 27 microM TBHP could be detected with a linear range from 6.6 x 10(-5) to 1.27 x 10(-2)M via amperometric method. The biosensor can reach 95% of the steady-state current in about 10+/-2s. More importantly, it can be applied in both hydrophilic and hydrophobic solvents without adding extra buffer or mediators to them that cannot be received by most traditional organic phase enzyme electrodes. This unique property greatly promotes the development of the organic phase enzyme electrodes by facilitating the detection of different kinds of substrates of the hemin-based artificial enzyme soluble in hydrophilic and hydrophobic solvents. The artificial enzyme electrode was successfully used to determine organic peroxides in body lotion samples.