Molybdenum disulfide nanosheet induced reactive oxygen species for high-efficiency luminol chemiluminescence

Luminol chemiluminescence (CL) sensing system remains an excellent candidate for application in bioanalysis due to its good water solubility. However, traditional luminol CL system usually requires the addition of oxidizing agents and sensitizers to obtain high efficiency for the improvement of detection sensitivity. Although numerous studies on the nanomaterial-enhanced luminol CL systems have been carried out, there is still great potential to develop inexpensive, readily available and easily handled catalysts to construct simple and effective CL platform for biomolecular sensing.

Few-layered MoS₂ nanosheets (NS) prepared by sonication-assisted exfoliation of commercially available bulk MoS₂ were found to significantly enhance the CL of luminol‒dissolved oxygen in the absence of additional oxidants. The mechanism study demonstrated that exfoliated MoS₂ NS could catalyze the decomposition of dissolved oxygen by virtue of its exposed active sites on the surface, generating increased reactive oxygen intermediates, which then oxidize luminol and produce intense CL emission. The proposed high-efficiency luminol CL system was then employed for the extremely sensitive identification of dopamine based on the quenching of CL by dopamine. The limit of detection (LOD) for dopamine can be as low as 2.07 nM. Besides, it also works well in the actual urine sample with good recoveries (99.6-100.6 %), confirming the practicability of the method.

As a new type of CL catalyst, MoS₂ NS developed in this work are easy to obtain, simple to prepare and can be produced in large quantities, which lays a foundation for extending applicability of MoS₂ NS in the CL field, and provides a new idea for developing simple and highly sensitive CL sensing system.