Wireless Electrochemical Visualization of Intracellular Antigens in Single Cells

Abstract

Electrochemical microscopy has been developed in the past decades for imaging biomolecules in single cells; however, electrochemical visualization of an intracellular protein in one cell is difficult. Herein, for the first time, we have developed a model whereby the protein, KDM1/LSD1 antigen, in the nucleus of a single MCF 7 cell could be visualized using wireless bipolar electrochemiluminescence (BPE-ECL). Submicron-sized, single-walled carbon nanotubes were linked with anti-KDM1/LSD1 antibodies and loaded into the cells for the recognition of the corresponding KDM1/LSD1 antigen. With a low electric field of 1000 V/cm, L012, a luminol analog, was oxidized electrochemically at one end of the nanotube that emitted light for the wireless visualization of its location. The significant drop in the applied voltage permitted the observation of apparent ECL emission inside the nucleus of a single cell, supporting the electrochemical imaging of intracellular KDM1/LSD1 antigen at a single-cell level. This work solves a long-standing task in the field of electroanalysis for intracellular wireless visualization, which should advance the development of electrochemistry in single-cell analysis.