Gold Nanobipyramid\nHotspot Aggregation-Induced Surface-Enhanced\nRaman Scattering for the Ultrasensitive Detection of miRNA

Abstract

Herein, a surface-enhanced Raman scattering (SERS) biosensor\nwas\nconstructed by gold nanobipyramid (Au NBP) hotspot aggregation-induced\nSERS (HAI-SERS) for the ultrasensitive detection of microRNA-221 (miRNA-221).\nImpressively, compared with single Au NBP, the multiple Au NBPs assembled\nby tetrahedral DNA nanostructures (TDNs) could increase hotspot aggregation\nto significantly enhance the SERS signal of Raman molecule methylene\nblue (MB). Meanwhile, in the aid of Exo-III assisted target cycle\namplification and TDNs-induced catalytic hairpin assembly (CHA) amplification,\nthe biosensor could achieve the sensitive detection of miRNA-221 with\na linear range of 1 fM–10 nM, and the limit of detection (LOD)\nwas 0.59 fM, which could be used for practical application in MHCC-97L\nand MCF-7 cell lysates. This work provided a method for hotspot aggregation\nto enhance SERS for the detection of biomarkers and disease diagnosis.