Development of MoS₂ Composites and Sensitive Detection of Amyloid β-Protein

Amyloid beta peptide (Aβ) has been considered as the hallmark of Alzheimer’s disease which is neurodegenerative disease and affects many senior citizens. However, drug for the treatment or control of such a disease is still lacking, thus early detection and intervention are particularly important. So far, fluorescence diagnose technique has been developed as an important mean for the detection of Aβ, but there are still many disadvantages in the traditional fluorescence techniques, such as low sensitivity, large background interference, and complicated operation. To address these issues, we synthesized a series of dicyanomethylene- 4H-pyran (DCM-OH) derivatives which were self-assembled with molybdenum disulfide (MoS₂) driven by π-π stacking interaction. The commercial products, resveratrol (Res) and thioflavine T (ThT), were used as the control group. The structures and purities of the three compounds were characterized by high resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC). The morphologies and structures of the three composites were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The characterization results display that the three prepared composites are regular and uniform, and can be used to detect indicators of AD in vitro. Moreover, we tested the applicability of the three composites in the detection of Aβ (1−40) and Aβ (1−42) in solution. The results show that the composites are capable of detecting Aβ (1−40) and Aβ (1−42) sensitively. In addition, the composite DCM-OH/MoS₂ was more sensitive for the detection of Aβ (1−42) with a LOD (Limit of Detection) of 6.8 nmol/L, which is 9.8 nmol/L for Aβ (1−42). Finally, we also tested the selectivity of the composite DCM-OH/MoS₂ against other proteins, and found that it showed better selectivity for Aβ. The results demonstrate that the developed system shows certain biological application prospects.