Evaluation of phage internalization into A431 and SKBR3 cells using confocal microscopy. A. Immunofluorescence Staining: (a) control fUSE5-ZZ-human IgG phages (b), no phage, only antibodies (c-l) serial cuts of A431 cells that were treated with fUSE5-ZZ-chFRP5 phages. Membranes were labelled by using red fluorescent CM-Dil cell tracker (MoBiTec, Göttingen, Germany). Phages were detected by monoclonal mouse anti-M13 followed by incubation with FITC conjugated goat anti-mouse IgG (green fluorescence). B. Evaluation of internalization of FITC labelled, drug conjugated phages into SKBR3 cells using confocal microscopy. a and b fUSE5-ZZ-chFRP5 phages, c and d control fUSE5-ZZ complexed with normal human IgG. As a reference, actin filaments with the cells were labelled by using red fluorescent dye Phalloidin (Sigma, Israel). Phages were labelled directly by FITC. Phages were added to the cells for 2 hr before analysis by confocal microscopy. Panels a and c show the green fluorescence of Fluorescein while in panels b and d the green fluorescence is overlaid on the red fluorescence.