Fig. 2.
The SIM–CFM allows simultaneous imaging of cells and matrix and measurement of force generation. Top left: CFM setup on Zeiss Axiovert epifluorescence microscope. Inset: freshly cast collagen matrix with embedded floatation bars and hooks to connect it to CFM suspension wires. Top right: working principles of the SIM–CFM. As fibroblasts contract matrix, a flexible metal strip connected to one of the embedded floatation bars is deflected. A force transducer converts the mechanical input into an electrical signal, which is recorded as force measurement on a PC. Cell behaviour and matrix interaction are visualised using light or confocal microscopy. Bottom: concomitant live cell imaging and contraction measurement on the SIM–CFM. HCF were seeded in collagen gels at a density of 106 cells/ml and placed on the SIM–CFM setup. Left image shows the cells in the gel 16 h after matrix preparation, as imaged live during contraction using DIC on an epifluorescence microscope with × 20 objective. Scale bar 50 μm. Right: corresponding force recording acquired simultaneously.