We developed a novel “signal-off” photoelectrochemical (PEC) aptasensor based on an aptamer bridged DNA network structure for the sensitive detection of vascular endothelial growth factor (VEGF₁₆₅), using g-C₃N₄ as photoactive material. The DNA network provides an excellent platform for the immobilization of methylene blue (MB), which can facilitate the electron transport through the DNA helix structure and suppress the recombination of electron-hole pairs generated by g-C₃N₄. In the presence of the target VEGF₁₆₅, the DNA network can be destroyed adequately by the recognition between VEGF₁₆₅ and the aptamer, resulting in the release of MB. Therefore, the originally enhanced electron transfer process could be inhibited, leading to a remarkable decrease of the photocurrent. A good linear relationship between the PEC signal and the logarithm of VEGF₁₆₅ concentration over the range of 100 fM to 10 nM with a detection limit of 30 fM can be obtained. Our concept can be easily extended to develop aptasensors for the sensitive detection of different targets by triggering the release of the payloads from their corresponding aptamer bridged DNA networks.

我们使用gC ₃ N ₄作为光敏材料，开发了一种基于适体桥式DNA网络结构的新型“信号关闭”光电化学（PEC）适体传感器，用于灵敏检测血管内皮生长因子（VEGF ₁₆₅）。DNA网络为亚甲基蓝（MB）的固定提供了一个极好的平台，它可以促进电子通过DNA螺旋结构的传输，并抑制gC ₃ N ₄产生的电子-空穴对的重组。在存在靶VEGF ₁₆₅的情况下，通过识别VEGF ₁₆₅可以充分破坏DNA网络和适体，导致MB的释放。因此，可以抑制最初增强的电子转移过程，从而导致光电流显着降低。在100 fM至10 nM的范围内，PEC信号与VEGF ₁₆₅浓度的对数之间具有良好的线性关系，检出限为30 fM。通过触发有效载荷从相应的适体桥接的DNA网络中释放出有效载荷，我们的概念可以轻松扩展为开发用于敏感检测不同目标的适体传感器。