Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, People's Republic of China.
Mikrochim Acta. 2019 Apr 10;186(5):275. doi: 10.1007/s00604-019-3393-x.
A "signal-off" sensor is described for sensitive photoelectrochemical (PEC) determination of the vascular endothelial growth factor (VEGF). Graphitic carbon nitride (g-CN) is used as the signalling material, and porous carbon spheres as efficient quenchers of the photocurrent. The quenching efficiency of carbon spheres is the result of two effects, viz. (a) the competitive light absorption and (b) competitive electron donor activity which decreases the number of light-generated electrons and holes and also reduces the charge separation efficiency. This new mechanism differs from the previous quenching mechanisms which usually are based on the suppression of electron transport or steric hindrance. A glassy carbon electrode was modified with an aptamer against VEGF. On binding of analyte (VEGF), the reduction of current is measured (at a typical potential of 0 V) using HO as the electrochemical probe. The sensor has a linear response in the 10 nM to 10 nM VEGF concentration range, and the detection limit is 3 fM. Graphical abstract Schematic presentation of the quenching mechanism of carbon spheres: the competitive light absorption and competitive electron donor reduce the number of light-generated electrons in the conduction band (CB) and holes in the valence band (VB) and also reduce the charge separation efficiency.
一种用于敏感光电化学（PEC）测定血管内皮生长因子（VEGF）的“信号关闭”传感器。使用石墨相氮化碳（g-CN）作为信号材料，多孔碳球作为光电流的有效猝灭剂。碳球的猝灭效率是两种效应的结果，即（a）竞争性光吸收和（b）竞争性电子给体活性，这降低了光生电子和空穴的数量，并降低了电荷分离效率。这种新的机制与以前的猝灭机制不同，以前的机制通常基于抑制电子传输或空间位阻。将玻碳电极用针对 VEGF 的适体修饰。在结合分析物（VEGF）后，使用 HO 作为电化学探针测量电流的减少（在典型的 0 V 电位下）。该传感器在 10 nM 至 10 nM VEGF 浓度范围内具有线性响应，检测限为 3 fM。示意图呈现碳球的猝灭机制：竞争性光吸收和竞争性电子给体减少了导带（CB）中的光生电子和价带（VB）中的空穴数量，也降低了电荷分离效率。
