AbstractThe authors describe the preparation of amino-functionalized carbon dots (NH2-CDs) via a one-step hydrothermal process using silver nitrate and chitosan as the precursors. The NH2-CDs have a fairly consistent size distribution with an average size of 2.8 ± 0.5 nm. This is attributed to the introduction of Ag(I) both as a catalyst and a precipitant. The NH2-CDs are highly crystalline. Their surface carries amino groups and carboxy groups which is confirmed by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Horseradish peroxidase (HRP) was immobilized in the NH2-CDs and then placed on a glassy carbon electrode (GCE). Spectroscopic and electrochemical analyses evidenced the stability and good bioactivity of the immobilized HRP. This reveals that NH2-CD is a desirable matrix for enzyme immobilization. The modified GCE exhibits enhanced electro-catalytic activity towards hydrogen peroxide (H2O2) reduction as compared to that of plain CDs. The effects of pH value and loading on the performances of the modified GCEs were studied. Under optimized conditions, the biosensor has a linear response in the 5 to 590 nM H2O2 concentration range, with a 1.8 nM defection limit (at an S/N ratio of 3). The sensor is stable, reproducible and selective. Finally, the sensor was applied to determine H2O2 in real samples, and satisfactory recoveries were achieved. Graphical abstractAmino-functionalized carbon dots (NH2-CDs) can provide more active sites and a friendly microenvironment for horseradish peroxidase (HRP) immobilization. Thus, a novel sensitive H2O2 biosensor has been developed.

中文翻译：

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将辣根过氧化物酶固定在氨基功能化碳点上以灵敏检测过氧化氢

摘要作者描述了使用硝酸银和壳聚糖作为前体通过一步水热法制备氨基功能化碳点 (NH2-CDs)。NH2-CD 具有相当一致的尺寸分布，平均尺寸为 2.8 ± 0.5 nm。这归因于引入 Ag(I) 作为催化剂和沉淀剂。NH2-CDs 是高度结晶的。它们的表面带有氨基和羧基，这通过透射电子显微镜 (TEM) 和傅里叶变换红外 (FTIR) 光谱证实。辣根过氧化物酶 (HRP) 被固定在 NH2-CDs 中，然后放置在玻璃碳电极 (GCE) 上。光谱和电化学分析证明了固定化 HRP 的稳定性和良好的生物活性。这表明 NH2-CD 是酶固定化的理想基质。与普通 CD 相比，改性 GCE 对过氧化氢 (H2O2) 还原表现出增强的电催化活性。研究了pH值和负载量对改性GCEs性能的影响。在优化条件下，生物传感器在 5 至 590 nM H2O2 浓度范围内具有线性响应，缺陷极限为 1.8 nM（信噪比为 3）。该传感器稳定、可重复且具有选择性。最后，将该传感器应用于实际样品中的 H2O2 测定，获得了满意的回收率。图形摘要氨基功能化碳点（NH2-CDs）可以为辣根过氧化物酶（HRP）的固定提供更多的活性位点和友好的微环境。因此，开发了一种新型灵敏的 H2O2 生物传感器。