School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, P. R. China.
Anal Chem. 2021 Aug 10;93(31):11043-11051. doi: 10.1021/acs.analchem.1c02488. Epub 2021 Jul 28.
DNA circuits as one of the dynamic nanostructures can be rationally designed and show amazing geometrical complexity and nanoscale accuracy, which are becoming increasingly attractive for DNA entropy-driven amplifier design. Herein, a novel and elegant exciton-plasmon interaction (EPI)-based photoelectrochemical (PEC) biosensor was developed with the assistance of a programmable entropy-driven DNA amplifier and superparamagnetic nanostructures. Low-abundance miRNA-let-7a as a model can efficiently initiate the operation of the entropy-driven DNA amplifier, and the released output DNAs can open the partially hybridized double-stranded DNA anchored on FeO@SiO particles. The liberated Au nanoparticles (NPs)-cDNA can completely hybridize with CdSe/ZnS quantum dots (QDs)-cDNA-1 and result in proportionally decreased photocurrent of CdSe/ZnS QDs-cDNA-1. This unique entropy-driven amplification strategy is beneficial for reducing the reversibility of each step reaction, enables the base sequence invariant and the reaction efficiency improvement, and exhibits high thermal stability and specificity as well as flexible design. These features grant the PEC biosensor with ultrasensitivity and high selectivity. Also, instead of solid-liquid interface assembly for conventional EPI-based PEC biosensors, herein, DNA hybridization in the solution phase enables the improved hybridization efficiency and sensitivity. In addition, superparamagnetic FeO@SiO particles further ensure the enhancement of the selectivity and reliability of the as-designed PEC biosensor. Particularly, this single-step electrode modification procedure evidently improves the electrode fabrication efficiency, reproducibility, and stability.
DNA 电路作为一种动态纳米结构，可以进行合理设计，并展现出惊人的几何复杂性和纳米级精度，这使其在 DNA 熵驱动放大器设计中越来越具有吸引力。在此，我们在可编程熵驱动 DNA 放大器和超顺磁性纳米结构的辅助下，开发了一种新颖而优雅的基于激子-等离子体相互作用（EPI）的光电化学（PEC）生物传感器。低丰度 miRNA-let-7a 作为模型可以有效地启动熵驱动 DNA 放大器的工作，并且释放的输出 DNA 可以打开固定在 FeO@SiO 颗粒上的部分杂交双链 DNA。释放的 Au 纳米颗粒（NPs）-cDNA 可以与 CdSe/ZnS 量子点（QDs）-cDNA-1 完全杂交，导致 CdSe/ZnS QDs-cDNA-1 的光电流比例降低。这种独特的熵驱动放大策略有利于减少每个反应步骤的可逆性，使碱基序列不变，提高反应效率，并表现出高的热稳定性和特异性以及灵活的设计。这些特性使 PEC 生物传感器具有超高的灵敏度和选择性。此外，与传统基于 EPI 的 PEC 生物传感器的固-液界面组装不同，本文在溶液相中进行 DNA 杂交，提高了杂交效率和灵敏度。此外，超顺磁性 FeO@SiO 颗粒进一步确保了所设计的 PEC 生物传感器的选择性和可靠性的增强。特别地，这种单步电极修饰程序明显提高了电极的制造效率、重现性和稳定性。
