Figure 3.
Mechano-imaging of integrins in live cell. (a) AFM image showing the typical AuNP sensor distribution. After 1 hr of cell culture on the sensor surface, the brightfield (b) and RICM image (c) were captured to visualize cell adhesion. RICM (c) clearly revealed the adhesion sites (dark region) mostly at the edge of the cell. (d) TIRF image (500 ms acquisition time) of the same cell shown in (b-c). The raw fluorescence data was converted to a quenching efficiency map using bulk quenching efficiency of AuNP sensor. A force map was then calculated using the WLC model. Inset shows rod-like focal adhesions with a high level of force. Scale bar, 20 μm. (g) Representative images showing that paxillin colocalizes with tension signals within focal adhesions. Scale bar, 15 μm.