Reusable dual-enhancement SERS sensor based on graphene and hybrid nanostructures for ultrasensitive lead (Ⅱ) detection

Abstract Lead (Pb2+) is the most common toxic heavy metal ion in the natural environment and causes enormous harm to public health for its non-metabolic accumulation. Therefore, it is essential to develop sensitive and robust system for detecting lead ions. Here, we provide a dual-enhancement (DE) surface-enhanced Raman scattering (SERS) strategy, that integrate the chemical enhancement of monolayer graphene and the electromagnetic enhancement of hybrid metal nanostructure, for sensitive quantitative detection of Pb2+ through enzyme-linked reaction principle. The enhancement factor (EF) of 3.85 × 108 of the DE SERS substrate was achieved. Pb2+ ions in water can be detected quantitatively through recording the Raman signal intensity of the Cy3. The results show that the developed SERS sensor owns a wide dynamic response range between 10 pM and 100 nM with a detection limit of 4.31 pM for Pb2+ detection. Furthermore, this high-quality SERS sensor possesses high Pb2+ specificity and can be recycled at least three times. In addition, the sensing mechanism of the SERS sensor is discussed and validated by the experiments and finite-difference time-domain (FDTD) simulations. The proposed dual-enhancement, reusable SERS sensor provides an effective approach for heavy ion detection and gene analysis in the field of environmental and life science and technology.