Growth Factor Receptor Imaging Analysis Based On Plasmonic Resonance Approach

Epidermal Growth Factor Receptor（EGFR）,as the member of the second largest family of proteins for cell signaling,plays a crucial role in cellular organized patterns,most cancers and targeted therapeutics.Surface Plasmon Resonance Imaging（SPRM）technology plays an important role in life analysis fields with its advantages of label-free,real-time and high temporal and spatial resolution.It is urgent to explore a real-time,in-situ,high-resolution single-cell study method to the study of EGF-induced activation of EGFR and its signaling pathway.SPRM technology was used to analyze the EGF-mediated EGFR activation and its downstream signaling pathway in A431 cells both at multicellular level,single-cell level and subcellular level.On multicellular and single cell level,A431 cells displayed a two-phase response to EGF.The positive SPR response in the first 600 s was related to the mass redistribution of EGFR activation,and the negative SPR signal in the subsequent phase was related to EGF-induced EMT events.At the same time,SPRM can effectively distinguish EGF-induced heterogeneity of A431 cells.What’s more,we succesffully detected the EC₅₀ of EGF to A431 cells of 2.5 nM.By the pre-treatment of two important inhibitors,we used SPRM for cell subcellular response analysis.AG1478inhibits the SPR response from the entire cell,whereas cytochalasin B strongly suppresses the SPR response from the cellular edge region.We have verified that SPRM is a valuable method for EGFR activation and its downstream signaling cascade analysis,which can easily be extended to the studies of cell responses triggered by the other specific molecules.This method offers abundant real-time and label-free multi-cell,single-cell and subcellular information with advanced resolution that can greatly facilitate our understanding of drug action and cancer-related molecular study.Through the surface plasmon resonance-impedance imaging method（P-EIM）,the SPR images and impedance images on the interface could be obtained at the same time,which can reflect the quality changes,concentration changes,and charge changes on the interface without label in real time.In this research,we constructed the P-EIM device and optimizated the vital parameters.P-EIM has potential to provide more information at subcellular level for the studies of EGF-mediated EGFR activation of A431 cells.