A Chiral‐Nanoassemblies‐Enabled Strategy for Simultaneously Profiling Surface Glycoprotein and MicroRNA in Living Cells

Assemblies of nanomaterials for biological applications in living cells have attracted much attention. Herein, graphene oxide (GO)–gold nanoparticle (Au NP) assemblies are driven by a splint DNA strand, which is designed with two regions at both ends that are complementary with the DNA sequence anchored on the surface of the GO and the Au NPs. In the presence of microRNA (miR)‐21 and epithelial cell‐adhesion molecule (EpCAM), the hybridization of miR‐21 with a molecular probe leads to the separation of 6‐fluorescein‐phosphoramidite‐modified Au NPs from GO, resulting in a decrease in the Raman signal, while EpCAM recognition reduces circular dichroism (CD) signals. The CD signals reverse from negative in original assemblies into positive when reacted with cells, which correlates with two enantiomer geometries. The EpCAM detection has a good linear range of 8.47–74.78 pg mL−1 and a limit of detection (LOD) of 3.63 pg mL−1, whereas miR‐21 detection displays an outstanding linear range of 0.07–13.68 amol ng−1RNA and LOD of 0.03 amol ng−1RNA. All the results are in good agreement with those of the Raman and confocal bioimaging. The strategy opens up an avenue to allow the highly accurate and reliable diagnosis (dual targets) of clinic diseases. Controllable chiral graphene oxide–gold assemblies are fabricated, which display dual strong optical signals with characteristic plasmonic circular dichroism (CD) at 521 nm and surface‐enhanced Raman scattering (SERS) at 1711.29 cm−1. Based on dual signals of plasmonic CD and SERS, for the first time, the quantitative monitoring of EpCAM and miR‐21 in living cells is achieved. Significantly, it is found that the CD signals reverse from negative in the original assemblies into positive when reacted with cell‐related biological components.