An efficient and low-cost surface-enhanced fluorescence substrate for trace detection of melamine in milk samples

Abstract

ObjectiveSurface-enhanced fluorescence (SEF) technology has wide application potential in the food security field. In this paper, an efficient and low-cost biological SEF substrate is designed for the trace detection of melamine in milk. MethodsThe substrate uses an easy to operate and stable magnetron sputtering system to modify the metal nanomaterials on lotus leaf (L.l.) surface(size: (1 cm × 1 cm). The SEF substrate (L.l.@Ag-25) with the best enhancement effect was selected by rhodamine 6 G (R6G), and the enhancement mechanism of fluorescence was analyzed by theoretical simulation. ResultThe filamentous structure on surface of L.l. was modified by metallic nanomaterials to form nanoparticles producing a good local surface plasmon resonance (LSPR) effect. There are high-density “hot spots” on L.l.@Ag-25 substrate, which generate strong electromagnetic fields and effectively enhance the fluorescence intensity of probe molecules. The L.l.@Ag-25 substrate has a low detection limit of 0.01 mg/L for melamine in milk samples, which is much lower than national detection standard. SignificanceThis filamentous structure of L.l surface provides a new strategy to the design and construction of SEF substrates, and establises potential application of detecting harmful substances in real environment,which has a good practical value.