Real-Time Synchrotron-based FTIR Spectromicroscopy of Molecular Signaling During Electrotaxis Initiation

Electrotaxis is an important cellular function for translocation during many cellular and developmental processes, such as wound healing, tumor cell metastasis, or tissue development. Current imaging approaches of studying signal transduction during electrotaxis often requires fluorescent tags. Here we present an experimental platform combining synchrotron infrared spectromicroscopy and a novel microfluidic electrotaxis chamber to allow label-free infrared spectroscopy study of live-cell electrotaxis in well-defined direct-current electric fields (dcEFs). We demonstrated that this novel approach enables us to measure the evolution of multiple molecular signaling events at sub-cellular resolutions, simultaneously, in live human corneal epithelial cells during their early response to dcEFs. Spatio-temporarily resolved spectra revealed both gradations of asymmetric patterns of protein phosphorylation and lipid-phase modification with an EF-guided directional preference, providing new insights into multi-molecular coordination during cellular signal transduction. We anticipate this powerful multiplex and label-free method will provide new opportunities and perspectives in understanding complex biological processes.