<p>The isolation and detection of circulating tumor cell (CTC) is of great significance for clinical cancer diagnosis and personalized therapy. Herein, a novel pangolin-type fluorescence imaging strategy is&#xa0;proposed to recognize, isolate and image CTC in whole blood. By combining ferroferric oxide (Fe₃O₄) nanoparticles modified with aptamer (Apt), poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1′,3}-thiadiazole)] (PFBT) and poly(styrene-co-maleic anhydride) (PSMA) formed in situ a large number of polymer dots (Pdots) on the surface of graphene oxide (GO), yielding a μm-sized 2D fluorescent probe Pdots@GO@Fe₃O₄-Apt. This probe could quickly recognize CTC and overlap each other on its surface, forming a “pangolin” structure where the CTCs were wrapped in a layer of “armor”. After rapidly separated from the sample by magnetic force, the morphology of the whole CTC could be observed by excited Pdots. The recognition, isolation and imaging of CTC were integrated in the probe, resulting in a high consistency between capture and imaging and ensuring high detection confidence. The feasibility of the pangolin-type fluorescence imaging strategy to detect CTC in actual samples was verified, demonstrating potential for clinical application.</p> Graphical abstract <p></p>