Size-dependent optical extinction of MoS2 nanosheets and their aptamer-induced dispersion behavior for the label-free detection of Escherichia coli O157:H7

Abstract

For aptamer-modified nanomaterial biosensors label-free detection methods are desirable due to them being simple and low in cost. Among these methods, nanomaterial aggregation for signal conversion is common, using materials such as gold nanoparticles. However, for MoS₂ nanosheets (MoS₂-NSs), signal conversion of its aggregation is difficult, resulting in the limited development of its label-free sensing applications. Herein, for the first time, the extinction spectrum has been employed to quickly transform the signal of MoS₂-NS aggregation and reveal the size-dependent extinction response of MoS₂-NS aggregation. Moreover, the size-dependent optical extinction behavior of MoS₂-NSs, using aptamers to induce the dispersion of the MoS₂-NSs and greatly improve their ability to identify targets, is studied. Importantly, this method has been employed to achieve the label-free detection of Escherichia coli O157:H7. The present investigation shows the promising use of MoS₂-NSs for the development of label-free detection.