CTC Immunofluorescence Assay : A Technique to Characterize Circulating Tumor Cells

- To begin, dilute the isolated circulating tumor cells or CTCs to the required concentration using an anti-binding solution that protects cells from fluid shear and pressure damage. Next, assemble a poly-lysine coated microscope slide and a cytocentrifuge filter card into a cytocentrifuge funnel assembly. Transfer the cell suspension into the funnel port of the assembly followed by cytocentrifugation.

The centrifugal force concentrates and deposits a monolayer of cells onto a circular area on the slide. Isolate the area deposited with cells using a silicone isolator. Once dry, fix the cells using paraformaldehyde. Next, incubate the cells with a suitable blocking solution containing proteins that bind readily to any non-specific binding sites on the cell surface.

Now, label the cells with a fluorescent-labeled antibody solution of interest. The fluorophore-tagged antibodies recognize and bind to specific target molecules on the cell surface. Wash the sample to remove any unbound antibodies. Add a mounting solution to prepare the sample for imaging.

Use a fluorescence microscope to detect the light emitted by the antibody-fluorophore conjugates bound to the target antigens on CTCs.