Pd@Pt Nanodendrites as Peroxidase Nanomimics for Enhanced Colorimetric ELISA of Cytokines with Femtomolar Sensitivity
Pd@Pt Nanodendrites as Peroxidase Nanomimics for Enhanced Colorimetric ELISA of Cytokines with Femtomolar Sensitivity
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DOI：
10.3390/chemosensors10090359
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
Zhuangqiang Gao;Chuanyu Wang;Jiacheng He;Pengyu Chen
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作者：
Zhuangqiang Gao;Chuanyu Wang;Jiacheng He;Pengyu Chen
比色酶联免疫吸附试验（ELISA）作为细胞因子检测的金标准方法已被广泛应用了几十年。然而，由于酶催化活性的限制，进一步提高ELISA的检测灵敏度已成为一个严峻的挑战。本文中，我们报道了使用Pd@Pt核@壳纳米树突（Pd@Pt ND）作为过氧化物酶纳米模拟物的用于超灵敏检测白细胞介素-6（IL-6，作为用于演示的模型细胞因子）的增强的比色ELISA（称为“Pd@Pt ND ELISA”），将灵敏度提高到飞摩尔水平。具体地，通过在Pd纳米立方体（NC）上沉积Pt原子以经由Volmer-Weber生长模式在Pd表面上产生粗糙的树枝状Pt皮肤来合理地设计Pd@Pt ND。它们可以大规模生产，具有高度均匀的尺寸，形状，组成和结构。它们表现出显著增强的过氧化物酶样催化活性，催化常数（Kcat）比辣根过氧化物酶（HRP，ELISA中常用的酶）高2000倍以上。使用Pd@Pt ND作为信号标记，Pd@Pt ND ELISA呈现用于定量测定IL-6的强比色信号，具有0.05-100 pg mL-1的宽动态范围和0.044 pg mL-1（1.7 fM）的超低检测限。该检测限比传统的基于HRP的ELISA低21倍。Pd@Pt ND ELISA的重现性和特异性极佳。更重要的是，Pd@Pt ND ELISA通过回收率测试被验证用于分析人血清样品中的IL-6，具有高准确性和可靠性。我们的研究结果表明，比色Pd@Pt ND ELISA是一种有前途的生物传感工具，用于超灵敏测定细胞因子，因此有望应用于各种临床诊断和基础生物医学研究。
Colorimetric enzyme-linked immunosorbent assay (ELISA) has been widely applied as the gold-standard method for cytokine detection over decades. However, it has become a critical challenge to further improve the detection sensitivity of ELISA as limited by the catalytic activity of enzymes. Herein, we report an enhanced colorimetric ELISA for ultrasensitive detection of interleukin-6 (IL-6, as a model cytokine for demonstration) using Pd@Pt core@shell nanodendrites (Pd@Pt NDs) as peroxidase nanomimics (named “Pd@Pt ND ELISA”), pushing the sensitivity up to femtomolar level. Specifically, the Pd@Pt NDs are rationally engineered by depositing Pt atoms on Pd nanocubes (NCs) to generate rough dendrite-like Pt skins on the Pd surfaces via Volmer-Weber growth mode. They can be produced on a large scale with highly uniform size, shape, composition, and structure. They exhibit significantly enhanced peroxidase-like catalytic activity with catalytic constants (Kcat) more than 2000-fold higher than those of horseradish peroxidase (HRP, an enzyme commonly used in ELISA). Using Pd@Pt NDs as the signal labels, the Pd@Pt ND ELISA presents strong colorimetric signals for the quantitative determination of IL-6 with a wide dynamic range of 0.05–100 pg mL-1 and an ultralow detection limit of 0.044 pg mL-1 (1.7 fM). This detection limit is 21-fold lower than that of conventional HRP-based ELISA. The reproducibility and specificity of the Pd@Pt ND ELISA are excellent. More significantly, the Pd@Pt ND ELISA was validated for analyzing IL-6 in human serum samples with high accuracy and reliability through recovery tests. Our results demonstrate that the colorimetric Pd@Pt ND ELISA is a promising biosensing tool for ultrasensitive determination of cytokines and thus is expected to be applied in a variety of clinical diagnoses and fundamental biomedical studies.