Abstract
As mechanical properties of scaffolds are implicated in cell behaviors, it is important to clarify the mechanical interaction between cells and materials for designing scaffolds. Here, we developed a fluorescence resonance energy transfer (FRET)-based mechanical sensor to visualize the interaction. The sensor consists of two fluorescent proteins linked with an elastic peptide, and its intramolecular FRET efficiency changes depending on the tension between the two fluorescent proteins. E. coli transgenic technology was used to produce the sensor protein, which was then purified (> 90%) and immobilized on a Cu-chelate glass plate. The results of FRET efficiency measurement and emission spectral acquisition showed that, compared to intermolecular FRET, intramolecular FRET occurred predominantly when the sensor proteins were immobilized on the plate. We then conducted a time-lapse fluorescent imaging of fibroblasts seeded on the sensor-immobilized plate. Low FRET index, which indicates strong tension, was observed at the edge of filopodia of the cell. These results suggest the visualization of the mechanical interaction between cells and the plate by the sensor.
