DNA‐Driven Two‐Layer Core–Satellite Gold Nanostructures for Ultrasensitive MicroRNA Detection in Living Cells
Dan Meng, Wei Ma, Xiaoling Wu, Chuanlai Xu, Hua Kuang
Abstract
Abstract It is a significant challenge to achieve controllable self‐assembly of superstructures for biological applications in living cells. Here, a two‐layer core–satellite assembly is driven by a Y‐DNA, which is designed with three nucleotide chains that hybridized through complementary sequences. The two‐layer core–satellite nanostructure (C 30 S 5 S 10 NS) is constructed using 30 nm gold nanoparticles (Au NPs) as the core, 5 nm Au NPs as the first satellite layer, and 10 nm Au NPs as the second satellite layer, resulting in a very strong circular dichroism (CD) and surface‐enhanced Raman scattering. After optimization, the yield is up to 85%, and produces a g ‐factor of 0.16 × 10 −2 . The hybridization of the target microRNA (miRNA) with the molecular probe causes a significant drop in the CD and Raman signals, and this phenomenon is used to detect the miRNA in living cells. The CD signal has a good linear range of 0.011–20.94 amol ng RNA −1 and a limit of detection (LOD) of 0.0051 amol ng RNA −1 , while Raman signal with the range of 0.052–34.98 amol ng RNA −1 and an LOD of 2.81 × 10 −2 amol ng RNA −1 . This innovative dual‐signal method can be used to quantify biomolecules in living cells, opening the way for ultrasensitive, highly accurate, and reliable diagnoses of clinical diseases.