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
过氧化氢（hydrogen peroxide, H2O2）；样品基质：磷酸盐缓冲液（PBS），未涉及实际生物/环境样品。
检测原理
传感器以GCE为基底，经APTES硅烷化后负载(PUI-NPs)/MWCNTs复合膜，再将Hb非共价包埋于膜中。PUI-NPs提供生物相容微环境，使Hb保持天然二级结构和血红素活性；MWCNTs形成导电网络，降低电子转移重组能并加速Hb与电极间的直接电子转移。在pH 7.0 PBS中，Hb血红素Fe3+/Fe2+在−0.346 V附近发生可逆直接电子转移。当H2O2加入时，Hb发挥过氧化物酶样催化作用，将H2O2还原为水，同时自身被再氧化，形成与H2O2浓度成正比的稳态还原电流。该过程无需外加酶或标记物，信号随H2O2浓度增加而线性增强。
检测灵敏度
LOD: 2.4 × 10−7 M；线性范围: 6.5 × 10−7–8.0 × 10−5 M；R^2 = 0.9815；Kappm: 0.155 mM
效应效果
该传感器对H2O2响应时间小于5 s，在0.1 mM H2O2下重现性RSD为2.56%(n=6)，同批六电极间RSD为8.7%。连续检测约2 h响应稳定，4 ℃ PBS中保存两周后仍保留91%初始电流。与文献报道的HZMS-SA、石墨烯-壳聚糖、NiO、CuO和Nafion/CuS等H2O2传感器相比，本文检出限0.24 μM和线性范围0.65–80 μM具有竞争力。文中未报告选择性/抗干扰及实际样品回收率。作者认为PUI-NPs可防止MWCNTs直接接触Hb，提供友好微环境，三维结构提高Hb负载量并促进底物扩散，因而适用于直接电化学、生物传感和生物催化。
传感器的构成
- 基底/换能器电极：玻璃碳电极(GCE)，抛光清洗后作为导电基底，承担电子转移与电流读出
- 界面修饰层：3-氨丙基三乙氧基硅烷(APTES)，乙醇溶液处理GCE，增强后续纳米复合膜附着
- 导电纳米修饰层：多壁碳纳米管(MWCNTs)，与PUI-NPs混合成膜，提供导电通道和三维结构，加速电子转移
- 生物相容纳米基质层：聚氨酯离子聚合物纳米粒子(PUI-NPs)，乳液聚合制备，形成微环境固定Hb并维持其天然构象
- 识别/催化元件：血红蛋白(Hb)，非共价包埋于(PUI-NPs)/MWCNTs膜中，保留血红素Fe3+/Fe2+直接电子转移和过氧化物酶样电催化活性
中文摘要
本研究报道了多壁碳纳米管(MWCNTs)非共价功能化聚氨酯离子聚合物纳米粒子(PUI-NPs)生物聚合物膜上血红蛋白(Hb)的生物电化学性质。PUI-NPs通过乳液聚合合成，可为Hb固定提供良好生物相容微环境。采用透射电镜(TEM)、扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)和圆二色光谱(CD)表征(PUI-NPs)/MWCNTs及Hb/(PUI-NPs)/MWCNTs复合膜。结果表明，固定化Hb在杂化膜中保持天然构象，并保留生物活性；在pH 7.0磷酸盐缓冲液中呈现良好电化学行为，形式电位为−0.346 V。pH 5.0–9.0范围内形式电位随pH线性变化，斜率为52.9 mV pH−1，表明一个质子参与电极反应。所得传感器对过氧化氢(H2O2)具有电催化活性，H2O2测定线性范围为6.5×10−7–8.0×10−5 M，检出限2.4×10−7 M，表观米氏常数Kappm为0.155 mM。研究证明该纳米结构聚合物可用于开发新型生物传感器。
英文摘要
This study described the bioelectrochemistry property of hemoglobin (Hb) on biopolymer film of polyurethane ionomer nanoparticles (PUI-NPs) noncovalently functionalized with multiwall carbon nanotubes (MWCNTs). The polyurethane ionomer nanoparticles (PUI-NPs) were synthesized by emulsion polymerization, and could provide a good biocompatible microenvironment for Hb immobilization. The characteristic of (PUI-NPs)/MWCNTs and Hb/(PUI-NPs)/MWCNTs composite films were performed by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and circular dichroism (CD). Analytical results indicated that the immobilized Hb could maintain its native conformation in the (PUI-NPs)/MWCNTs hybrid film. Entrapped Hb in (PUI-NPs)/MWCNTs preserved its bioactivities and exhibited an excellent electrochemical behavior with a formal potential of -0.346 V in a pH 7.0 phosphate buffer. The formal potential of Hb varied linearly with the increase of pH in the range of 5.0-9.0 with a slope of 52.9 mV pH(-1), indicating that one proton participated in the electrochemical reaction process. Moreover, the resulting biosensor displays an electrocatalytic activity to hydrogen peroxide (H(2)O(2)). The linear range for the determination of H(2)O(2) was from 6.5×10(-7) to 8.0×10(-5)M with a detection limit of 2.4×10(-7)M and a Michaelis-Menten constant K(m)(app) value of 0.155 mM. Consequently, our investigation demonstrated that the proposed method opens a way to develop biosensors by using polymer with good biocompatible in its nanostructured information.