Immunofluorescence microscopy of cathepsin B presence (green, emission 620nm), DAPI-stained DNA in cell nuclei (blue, emission 460nm) and protease sensor activation (red, emission 700nm) shows colocalisation in atherosclerotic plaques (yellow, arrows). Left panel shows histology from apoE−/− mouse injected with PS-5, middle PS-25, and right PS-40. The error bar denotes 50µm.