State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China.
Anal Chem. 2019 Aug 6;91(15):9993-10000. doi: 10.1021/acs.analchem.9b01826. Epub 2019 Jul 26.
Molecularly imprinted polymers (MIPs), which are synthesized in the presence of a template, have been widely used as antibody mimics for important applications. Through the combination with a highly sensitive detection scheme such as chemiluminescence and surface-enhanced Raman scattering (SERS), MIP-based sandwich assays have emerged as promising analytical tools for the detection of disease biomarkers. However, so far, MIPs have been used only as target-capturing probes, whereas labeling by other means was needed, which limits the application range. Herein, we present a new approach, called a dual MIP-based plasmonic immunosandwich assay (duMIP-PISA), for the specific and sensitive detection of protein biomarkers in complex biological samples. A C-terminal epitope-imprinted self-assembled gold nanoparticle monolayer-coated glass slide was prepared as a plasmonic substrate for the specific extraction of target protein, while N-terminal epitope-imprinted Raman-responsive Ag@SiO nanoparticles were prepared as nanotags for the specific labeling of captured protein. The formed MIP-protein-MIP sandwich-like complexes could produce a significantly enhanced SERS signal. The dual MIP-based recognitions ensured high specificity of the assay, while SERS detection provided ultrahigh sensitivity. The duMIP-PISA of neuron-specific enolase (NSE) in human serums was demonstrated, which permitted the differentiation of small cell lung cancer patients from healthy individuals. As compared to regular ELISA, the duMIP-PISA exhibited multiple merits including a simpler procedure, faster speed, lower sample volume requirement, and wider linear range. The approach well demonstrated the great potentials of MIPs and can be easily modified and extended to other protein biomarkers. Therefore, the duMIP-PISA approach holds great promise in many important applications such as disease diagnosis.
分子印迹聚合物（MIPs）是在模板存在的情况下合成的，已被广泛用作抗体模拟物，用于重要的应用。通过与化学发光和表面增强拉曼散射（SERS）等高灵敏度检测方案结合，基于 MIP 的夹心测定法已成为用于检测疾病生物标志物的有前途的分析工具。然而，迄今为止，MIP 仅被用作靶标捕获探针，而需要其他标记方法，这限制了其应用范围。在此，我们提出了一种新方法，称为基于双重分子印迹的等离子体免疫夹心测定法（duMIP-PISA），用于在复杂生物样品中特异性和灵敏地检测蛋白质生物标志物。作为用于特定提取靶蛋白的等离子体基底，制备了末端表位印迹的自组装金纳米粒子单层涂覆的玻璃片；同时，制备了末端表位印迹的拉曼响应性 Ag@SiO2 纳米颗粒作为捕获蛋白的纳米标签。形成的 MIP-蛋白质-MIP 三明治样复合物可以产生显著增强的 SERS 信号。基于双重 MIP 的识别确保了该测定法的高特异性，而 SERS 检测则提供了超高的灵敏度。在人血清中对神经元特异性烯醇化酶（NSE）进行了 duMIP-PISA 测定，这使得能够区分小细胞肺癌患者和健康个体。与常规 ELISA 相比，duMIP-PISA 具有多个优点，包括更简单的过程、更快的速度、更低的样品体积要求和更宽的线性范围。该方法很好地证明了 MIP 的巨大潜力，并且可以轻松地修改和扩展到其他蛋白质生物标志物。因此，duMIP-PISA 方法在疾病诊断等许多重要应用中具有广阔的应用前景。
