Sensitive immunosensor for the label-free determination of tumor marker based on carbon nanotubes/mesoporous silica and graphene modified electrode

► Acidic-pretreated SWCNTs were confined inside the channels of mesoporous silica. ► SWCNTs and graphene sheets promoted the electron transportation through the channel. ► Electron transfer from solution to electrode surface was confined inside the channel. ► Label-free detection simplifies the manipulation by monitoring the current changes.