Developing a simple and sensitive method for detecting tumor biomarkers is practically important for early diagnosis and clinical treatment of diseases. However, it is still the major challenge to improve the sensitivity and accuracy. Here, “a dual-signal read out mode” ratiometric electrochemical immunosensor was developed based on well-dispersed hierarchical PtCoNi hollow multi-branches (HMBs)/ferrocene-grafted-ionic liquid (Fc-g-IL, synthesized via Schiff-base reaction) and CoNC nanosheets (NSs, obtained by a simple pyrolysis method) as signal amplification. Specifically, the PtCoNi HMBs were synthesized by solvothermal treatment and then etched with acetic acid. The PtCoNi HMBs/Fc-g-IL showed improved catalytic property and superior biocompatibility. Meanwhile, Au nanostars/thionine decorated CoNC NSs (Au-Thi-Co-N-C NSs) performed as the label of secondary antibody (Ab₂) to greatly enhance the signals. This immunoassay for N-terminal pro-B-type natriuretic peptide (NT-proBNP) was realized by boosting the Thi signals while inversely decaying the Fc responses, in turn showing the linear relationship towards the analyte in the range of 0.001–10.0 ng mL^–1 with the low detection limit down to 0.35 pg mL^–1 (S/N = 3). This study displays a promising platform for determination of other tumor biomarkers in real medical applications.

开发一种简单而灵敏的方法来检测肿瘤生物标志物对于疾病的早期诊断和临床治疗实际上具有重要意义。但是，提高灵敏度和准确性仍然是主要挑战。在此，“双信号读出模式”比例电化学免疫是基于良好分散的分层PtCoNi中空多分支（HMBS）/二茂铁-接枝的离子型液体（FC-G-IL，合成开发通过席夫碱反应）和Co NC纳米片（NS，通过简单的热解方法获得）作为信号放大。具体地，通过溶剂热处理合成PtCoNi HMB，然后用乙酸蚀刻。PtCoNi HMBs / Fc-g-IL显示出改善的催化性能和优异的生物相容性。同时，金纳米星/蛋氨酸修饰的Co N C NSs（Au-Thi-Co-NC NSs）作为二抗（Ab ₂）的标记发挥作用，大大增强了信号。N端前B型利钠尿肽（NT-proBNP）的免疫测定是通过增强Thi信号，同时使Fc反应反向衰减而实现的，从而显示了与分析物的线性关系，范围为0.001–10.0 ng mL ^–1，低检测限低至0.35 pg mL^–1（S / N  = 3）。这项研究显示了一个有前途的平台，用于确定实际医学应用中的其他肿瘤生物标记。