A Dual Co-Reactant Accelerator Based On Nanoreactor-Encapsulated CeO2 Nanozymes to Drive Potentiated Luminol Cathodic Electrochemiluminescence for Ultrasensitive Immunoassay

en This link goes to a English section zh This link goes to a Chinese section The precise quantification of cytokines is crucial for monitoring disease onset and progression. Herein, we developed a synergistic signal amplification approach by utilizing nanoreactor-encapsulated CeO 2 nanozymes, which were in situ electrodeposited within the mesoporous silica nanochannel film (SNF) grown on indium tin oxide (ITO) electrodes (CeO 2 @SNF/ITO). Notably, CeO 2 @SNF/ITO possesses bifunctional enzyme-like activities, enabling efficient regulation of two co-reactants, including endogenous dissolved oxygen (DO) and exogenous hydrogen peroxide (H 2 O 2 ). Under neutral pH conditions, electrochemical reduction of the encapsulated CeO 2 leads to the transformation of Ce(IV) into Ce(III). The resulting Ce(III) species not only facilitates the oxygen reduction reaction through its oxidase-like activity but also catalyzes H 2 O 2 decomposition via peroxidase-like behavior. This process leads to the abundant generation of reactive oxygen species (ROS), which can effectively oxidize luminol anions, thereby significantly enhancing the cathodic electrochemiluminescence (ECL) signal. The reversible Ce(III)/Ce(IV) redox cycle also confers outstanding electrode reusability. As a proof of concept, an immunosensor for selective detection of the cytokine interleukin 6 (IL-6) was constructed by modifying the outer surface of the SNF. The proposed immunosensor exhibits high sensitivity for IL-6 detection, achieving a remarkably low detection limit of 2.5 fg mL −1 over a concentration range from 10 fg mL −1 to 10 ng mL −1 . This work offers a promising avenue for expanding the functional scope of SNF-confined nanozymes in advanced ECL systems for immunosensing. 摘要 en This link goes to a English section zh This link goes to a Chinese section 细胞因子的精确定量对监测疾病的发生与进展至关重要。在此,我们利用纳米反应器封装CeO 2 纳米酶,开发了一种协同的信号放大方法。通过原位电沉积技术将CeO 2 纳米酶封装于生长在氧化铟锡(ITO)电极上的介孔二氧化硅纳米通道薄膜(SNF)内,制备CeO 2 @SNF/ITO。值得注意的是,CeO 2 @SNF/ITO具有双重类酶活性,能够高效调控内源性溶解氧(DO)和外源性过氧化氢(H 2 O 2 )两种共反应物。在中性pH条件下,通过电化学还原可以使封装的CeO 2 中的Ce(IV)转化为Ce(III)。生成的Ce(III)不仅可以凭借其类氧化酶活性促进氧还原反应,还能通过类过氧化物酶行为催化H 2 O 2 分解。上述两个过程可积累大量的活性氧物种(ROS),有效氧化鲁米诺阴离子(LH − ),从而显著增强阴极电化学发光(ECL)。可逆的Ce(III)/Ce(IV)氧化还原循环还赋予了电极出色的可重复使用性。作为概念验证,通过在SNF外表面修饰抗体,构建了用于细胞因子白细胞介素-6(IL-6)检测的免疫传感器。该传感器能够实现对IL-6的超灵敏检测,检测线性范围为10 fg mL −1 至10 ng mL −1 ,检测限低至2.5 fg mL −1 。