College of Chemistry, Chemical engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, People's Republic of China.
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, Suzhou, People's Republic of China.
Mikrochim Acta. 2018 Jan 15;185(2):114. doi: 10.1007/s00604-017-2629-x.
The authors describe the preparation of amino-functionalized carbon dots (NH-CDs) via a one-step hydrothermal process using silver nitrate and chitosan as the precursors. The NH-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 NH-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 NH-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 NH-CD is a desirable matrix for enzyme immobilization. The modified GCE exhibits enhanced electro-catalytic activity towards hydrogen peroxide (HO) 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 HO 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 HO in real samples, and satisfactory recoveries were achieved. Graphical abstract Amino-functionalized carbon dots (NH-CDs) can provide more active sites and a friendly microenvironment for horseradish peroxidase (HRP) immobilization. Thus, a novel sensitive HO biosensor has been developed.
作者描述了一种通过一步水热法使用硝酸银和壳聚糖作为前体制备氨基功能化碳点（NH-CDs）的方法。NH-CDs 的粒径分布相当均匀，平均粒径为 2.8±0.5nm。这归因于 Ag(I) 的引入，Ag(I) 既作为催化剂又作为沉淀剂。NH-CDs 具有很高的结晶度。透射电子显微镜（TEM）和傅里叶变换红外（FTIR）光谱证实其表面带有氨基和羧基。辣根过氧化物酶（HRP）被固定在 NH-CDs 中，然后放置在玻碳电极（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 NH-CD 是酶固定化的理想基质。与普通 CDs 相比，修饰后的 GCE 对过氧化氢（HO）还原表现出增强的电催化活性。研究了 pH 值和负载量对修饰后的 GCE 性能的影响。在优化条件下，该生物传感器在 5 至 590 nM HO 浓度范围内呈线性响应，检出限为 1.8 nM（信噪比为 3）。传感器具有稳定性、重现性和选择性。最后，该传感器被用于测定实际样品中的 HO，获得了令人满意的回收率。
