This work reports on a molybdenum disulfide (MoS₂) based field-effect transistor (FET) biosensor for ultrasensitive label-free detection of DNA via phosphorodiamidate morpholino oligos (PMO)-DNA hybridization. After the chip was fabricated and the sensing channel was modified with positive charges, the negatively charged MoS₂ nanosheet was drop-casted onto the channel, enabling MoS₂ to tightly bind to the sensing surface via electrostatic interactions. Meanwhile, DNA analogue, PMO, was immobilized on the MoS₂ surface, and detection of PMO-DNA hybridization was conducted by the fabricated MoS₂ FET biosensor. Due to the neutral character and high affinity of PMO, a limit of detection (LOD) down to 6 fM was obtained, which is lower than that of the previously reported MoS₂ FET DNA biosensor based on DNA-DNA hybridization. In addition, the MoS₂ FET biosensor also showed high sequence specificity capable of distinguishing the complementary DNA from one-base mismatched DNA, three-base mismatched DNA and noncomplementary DNA. Moreover, the unique FET biosensor was able to detect DNA in complex sample like serum, making the method potential in disease diagnostics.

这项工作报告了基于二硫化钼（MoS ₂）的场效应晶体管（FET）生物传感器，用于通过二氨基氨基磷酸吗啉代寡核苷酸（PMO）-DNA杂交对DNA进行超灵敏的无标记检测。芯片制造完成并使用正电荷修饰感测通道后，将带负电荷的MoS ₂纳米片滴铸到通道上，从而使MoS ₂可以通过静电相互作用紧密结合到传感表面。同时，将DNA类似物PMO固定在MoS ₂表面上，并通过制造的MoS ₂进行PMO-DNA杂交的检测。FET生物传感器。由于PMO的中性特征和高亲和力，获得了最低6 fM的检测限（LOD），该限度低于以前报道的基于DNA-DNA杂交的MoS ₂ FET DNA生物传感器的检测限。此外，MoS ₂ FET生物传感器还显示出高序列特异性，能够区分互补DNA与一碱基错配DNA，三碱基错配DNA和非互补DNA。此外，独特的FET生物传感器能够检测复杂样品（如血清）中的DNA，使该方法在疾病诊断中具有潜力。