Phalloidin-based fluorimetric quantitation of cells on plates and polycarbonate membranes

An in vitro, fluorimetric method for the quantitation of immobilized cells has been developed using sulfarhodamine-labeled phalloidin. This actin-based microtiter assay has a number of important advantages over conventional cellular quantitation methods. It does not require prior labelling of cells, works well on either plates or polycarbonate membranes, and is rapid, automatable and quantitative. We have optimized the assay using cultured human lung cancer cells. Although special emphasis has been placed on the attachment of CD44-positive cells to hyaluronan, the method detects cellular attachment to a variety of substrates including laminin and fibronectin. The porous surfaces used are identical to those employed in conventional chemotaxis and invasion assays. As such, this detection method may provide a useful means to identify anti-adhesives and invasives and represents an alternative to the initial phases of animal testing.