A novel SERS biosensor for ultrasensitive detection of mercury(II) in complex biological samples

Developing highly sensitive and specific method is essential for trace Hg 2+ quantifying. Herein, we established a background-free surface-enhanced Raman scattering (SERS) platform which allows not only the detection of Hg 2+ in homogeneous samples, but also high-precision profiling of Hg 2+ distribution in zebrafish. Its superior anti-interference capability is due to the introduction of a high signal-to-noise-ratio (SNR) Raman reporter with an acetylenyl group, which present single nonoverlapping peak at 2125 cm −1 , avoiding interference from other substances. Additionally, the specific recognition of Hg 2+ -bis-thymine complexes and the signal amplified hybridization chain reaction (HCR) were effectively utilized in this design. Benefited from the above strategies, a detection range for Hg 2+ from 1.0 fM to 100 pM was achieved with a detection limit of 0.2 fM. Additionally, Raman imaging was first performed in zebrafish sections to study Hg 2+ distribution which provided a reference for the detection of Hg 2+ pollution in fish. This approach could be extended to target other interested analytes both in simple and biological samples for various purposes.