JACS reports the research progress of jiangdechen research group of Nanjing University in single cell surface protein marker free imaging

The study of protein content and distribution on cell and sensor surface is helpful to elucidate the molecular mechanism in cell biology Since the analysis process is simple and the interference to the measurement system is small, the analysis of marker free protein imaging has attracted much attention In recent years, many kinds of marker free technologies have been developed, but how to build a high sensitivity and simple imaging system is still a challenge Recently, based on the long-term accumulation of electrochemiluminescence (ECL) microscopic imaging in the early stage, jiangdechen research group, School of chemistry and chemical engineering of Nanjing University and State Key Laboratory of life analytical chemistry, designed a new capacitance microscope based on ECL signal, and successfully realized the unmarked imaging analysis of electrode and single cell surface antigen molecules The core of the technology is that the binding of protein molecules to the surface will cause the capacitance of the binding area to decrease, which makes the voltage drop of the double electric layer in this area relatively high Since the luminol's luminous intensity is highly dependent on the voltage drop of the double electric layer on the electrode surface, the binding region will produce strong ECL light signals, which can be effectively separated from the surrounding region, and realize the visualization of protein molecules The system has high detection sensitivity, and the CEA of Ag (10-18 g) can be observed on the electrode surface The device only contains a common optical microscope, voltage generator and CCD camera, so it is simple and convenient Furthermore, the CEA antigen on the surface of single cell was visualized directly by the antigen antibody complex formed by antibody on the surface of cell This capacitance microscope can not only detect the protein on the cell surface without markers, but also provide a new analysis strategy for high sensitive biomolecule detection The work was published in J am Chem SOC (DOI: 10.1021 / JACS 9b0307) as "electrochemically based capacity microscopy for label free imaging of antigens on the cellular plasma membrane" Zhang Jingjing, a doctoral student of Nanjing University, is the first author of this paper, Professor Jiang Dechen is the corresponding author, and academician Chen Hongyuan has given important guidance to this work This research was supported by the key R & D project of the Ministry of science and technology of the people's Republic of China (2016yfa0201200), the major instrument project of NSFC (21327902) and the excellence program of Nanjing University (zyjh004)