基于靶标酶解反应的光电化学生物传感及血样分析研究

As the abnormal expression of phosphatase is closely related to human health and disease, it is urgent to construct highly efficient phosphatase nanobiosensor for early diagnosis, and treatment monitoring. So far, the nanobiosensor faces problems as complex probe design, poor stability, low sensitivity and so on. Based on the previous research, enzymolysis products of targets is available to in situ modify photoelectrode, thus improving the photocurrent intensity. In this project, we will focus on the development of nano interface-based sensing platform to realize the efficient and sensitive phosphatase detection in whole blood. Through preparing 2D copper phosphate as photoelectrode material, and screening suitable substrate of phosphatase, not only the phosphate group derived from the enzymatic hydrolysis can facilitate passivation of surface states in a semiconductor, but also the reduction product can assist in generating noble metal nanoparticle on the surface of photoelectrode to promote the local surface plasmon resonance (LSPR) absorption, resulting in an increase of the density of free carriers. Meanwhile, adjust the vertically alignment of 2D copper phosphate to ensure efficient signal conversion and output for the PEC signal amplification. Besides, phosphatase-related specific antibodies are screened and applied to obtain good selectivity and accuracy. This project is expected to blaze a new trail for nano interface-based biosensing construction.

磷酸酶的异常表达与人体前列腺癌、骨疾病等紧密相关，开发准确灵敏的纳米生物传感实现体内磷酸酶检测，对相关疾病早期诊断具有重要临床意义。目前，纳米生物传感在磷酸酶检测中存在探针设计复杂、稳定性差、灵敏度低等问题。前期研究发现，靶标酶解产物可实现传感界面的实时有效修饰，促使光电流强度提高。本项目拟采用纳米界面信号转导检测模式，开发简单稳定的光电化学生物传感，实现血样中痕量磷酸酶的高效灵敏检测。基于光电极载体二维磷酸铜的优良特性，筛选合适的磷酸酶底物，分别利用酶解产物磷酸根有效修复半导体表面缺陷态提高载体材料的光电活性，及还原性产物原位贵金属修饰提高基于局域表面等离子体共振效应的光利用率，促使自由载流子浓度增加。同时，调控二维磷酸铜垂直排列确保传感界面高效信号转换与输出，实现信号放大。此外，筛选磷酸酶特异性识别抗体，提高传感检测的特异性。本项目将为信号转导传感界面设计及高效靶标分析提供新思路。

人体内磷酸酶的异常表达与人体前列腺癌、骨疾病等紧密相关，实现其精准可靠分析对相关疾病的早期诊断具有重要临床意义。本项目通过纳米界面信号转导检测模式，针对光电化学传感构筑过程中存在的探针设计复杂、稳定性差、灵敏度低等问题，开发出可用于碱性磷酸酶等多种生物标志物分析的高灵敏检测方法，并深入探究了其信号放大及光电化学传感机理。利用微乳法成功合成了二维超薄磷酸铜纳米片，其片层厚度低至2 nm，发展出多种可用于光电极基底修饰的磷酸铜基复合纳米材料。通过筛选导热系数相差较大的两种材料，将其分别切割成楔形再拼接成矩形模具（以确保模具表面的导热速率呈线性增减），开发了基于定向梯度冷冻干燥技术的二维纳米材料在基底垂直有序排列的精准调控方法。利用二维片层纳米复合材料作为光电极修饰材料及定向梯度冷冻干燥技术精准调控材料在光电极基底的有序排列，发展了以碱性磷酸酶为代表的多种不同生物标志物的光电化学检测新方法，提高了分析传感性能，减低了检测结果的假阳性率。结合实际样本和大数据分析对建立的生物标志物分析方法进行验证，进一步修饰了研究方法，提高了检测方法的准确性。通过本项目的研究，为发展基于纳米界面信号转导检测模式的光电化学高效靶标分析技术提供了新思路，可有效协助多种疾病的早期诊断、指导治疗和预后判断。