In-situ and amplification-free imaging of hERG ion channels at single-cell level using a unique core-molecule-shell-secondary antibody SERS nanoprobe

Research on ion channels and their monoclonal antibodies plays a critical role in drug development and disease diagnosis. The current ion channel researches are often not conducted in the microenvironment for cells survival , which restricts the mechanism study of the links between the cell structure and the ion channel function. In this work, we synthesized gold core-4-mercaptobenzonitrile-sliver shell-goat anti-rabbit immunoglobulin G ( [email protected] @ [email protected] ) nanoparticles as surface-enhanced Raman scattering (SERS) nanoprobes for investigating the human ether-a-go-go related gene (hERG) potassium ion channel in cell membranes. This is the first attempt to study ion channels using SERS. Due to the unique core-molecule-shell structure and the silver shell of nanoprobes, strong and stable SERS signal was obtained. With the help of antibodies, the [email protected] @ [email protected] nanoprobes were captured by hERG antibodies and then bonded with hERG ion channels based on the sandwich immune response. The reporter molecule, 4-MBN, displayed a strong and sharp characteristic peak at 2233 cm - 1 in the Raman silent region. The intensity of this peak denoted the concentration of antibodies and the expression of ion channel proteins. We successfully applied this amplification-free method for in-situ imaging the distribution of the hERG ion channel on the transfected HEK293 cell surface at the single-cell level. This hERG ion channel profiling strategy promises a maneuverable tool for ion channel research.