组成图示
示意图生成中
传感器类型
电化学生物传感器
检测对象
过氧化氢（hydrogen peroxide, H2O2），样品基质为0.05 M磷酸盐缓冲液（PBS, pH 6.8）。
检测原理
传感器以PANI导电聚合物膜作为非扩散性电子介体，将HRP血红素活性中心的电子转移至Pt电极。HRP通过静电作用固定于PANI膜表面，保持催化活性。当H2O2扩散到电极界面时，HRP催化其还原，PANI在酶与电极间穿梭电子，使H2O2在约-400 mV处发生电催化还原并产生阴极电流。在扩散控制条件下，催化电流随H2O2浓度增加而增大；当[H2O2]低于表观Michaelis–Menten常数K′M时，电流与浓度呈线性关系，斜率Imax/K′M代表灵敏度。方波伏安和循环伏安用于读取该催化电流。
检测灵敏度
线性范围: 2.5×10−4–5×10−3 M；灵敏度斜率: 2.88×10−2 A mol−1 dm3；R^2 = 0.995
效应效果
该传感器在2.5×10−4–5×10−3 mol L−1范围内对H2O2线性响应，r2=0.995，斜率2.88×10−2 A mol−1 dm3。作者认为性能不及文献，主要因固定酶浓度低（0.08 g L−1）、PANI电子扩散系数低（8.68×10−9 cm2 s−1）及II型HRP纯度较低。SEM显示HRP固定后PANI表面呈斑点状蛋白聚集体；1 mM H2O2循环伏安后聚集体减少，提示弱静电固定可能致酶流失或H2O2抑制。文中未报告选择性、抗干扰、稳定性或实际样品回收率。作者强调其膜厚可控、信号放大、制备简便，并可用于丝网印刷碳电极一次性应用。
传感器的构成
- 工作电极基底：铂盘电极（Pt disk electrode），面积1.77×10−2 cm2，作为导电基底；丝网印刷碳电极（SPCE）用于SEM形貌研究。
- 导电聚合物修饰层：聚苯胺（PANI），在0.2 M苯胺/1 M HCl中电位动态电聚合，作为电子介体与酶固定载体。
- 识别/催化元件：辣根过氧化物酶（HRP），在+650 mV下静电固定于PANI膜，催化H2O2还原。
- 电解质介质：0.05 M磷酸盐缓冲液（PBS, pH 6.8），提供离子导电与酶催化环境。
- 信号读出装置：BAS/50W电化学工作站，配合Ag/AgCl参比电极和铂丝网辅助电极，通过循环伏安（CV）和方波伏安（SWV）读取催化电流。
中文摘要
本文报道了一种基于聚苯胺（PANI）和辣根过氧化物酶（HRP）的安培型生物传感器。通过在盐酸介质中对铂盘电极进行循环伏安电聚合，原位沉积PANI导电聚合物膜；在1 M HCl中，PANI膜呈现两组明显可逆氧化还原峰，表明其具有快速可逆电化学活性。根据Brown–Anson模型估算，PANI表面浓度约为1.85×10−7 mol cm−2，膜厚约16 nm。随后在+650 mV下将HRP通过静电作用固定于PANI膜表面，利用方波伏安法和循环伏安法监测过氧化氢（H2O2）的电催化还原。在扩散控制条件下，传感器对H2O2在2.5×10−4–5×10−3 mol L−1范围内呈线性响应。光谱电化学用于观察HRP在催化H2O2前后的紫外–可见吸收变化；扫描电镜则用于表征PANI修饰丝网印刷碳电极在有无HRP和H2O2条件下的表面形貌，结果显示HRP掺杂及H2O2作用均引起导电膜表面结构明显改变。
英文摘要
An amperometric biosensor was prepared by in situ deposition of horseradish peroxidase (HRP) enzyme on a polyaniline (PANI)-doped platinum disk electrode. The PANI film was electrochemically deposited on the electrode at 100mVs(-1)/Ag-AgCl. Cyclic voltammetric characterization of the PANI film in 1M HCl showed two distinct redox peaks, which prove that the PANI film was electroactive and exhibited fast reversible electrochemistry. The surface concentration and film thickness of the adsorbed electroactive species was estimated to be 1.85x10(-7)molcm(-2) and approximately 16nm, respectively. HRP was electrostatically immobilized onto the surface of the PANI film, and voltammetry was used to monitor the electrocatalytic reduction of hydrogen peroxide under diffusion-controlled conditions. Linear responses over the concentration range 2.5x10(-4) to 5x10(-3)M were observed. Spectroelectrochemistry was used to monitor the changes in UV-vis properties of HRP, before and after the catalysis of H(2)O(2). The biosensor surface morphology was characterized by scanning electron microscopy (SEM) using PANI-doped screen-printed carbon electrodes (SPCEs) in the presence and absence of (i) peroxidase and (ii) peroxide. The SEM images showed clear modifications of the conducting film surface structure when doped with HRP, as well as the effect of hydrogen peroxide on the morphology of biosensor.