Accurate diagnosis of cancer at an early stage is the key to reduce cancer mortality and improve survival. PET imaging has high sensitivity but low spatial resolution, while CT imaging has good spatial location information. Therefore, the combination of PET and CT imaging can provide complementary advantages to achieve accurate early diagnosis of tumors. However, currently developed PET or CT imaging agents have only a single function. Here, we designed and constructed a self-assembled lipid nanocapsule encapsulated with iodixanol and labeled with self-chelated 64Cu for precise PET/CT imaging of tiny lung tumor. The lipid nanocapsule self-assembled in water using LPPC-Ce6, a conjugate of chlorin e6 (Ce6) and lysophosphatidylcholine (LPPC), to form a bilayer vesicular structure. 64Cu was embedded in the center of the tetrapyrrole ring of Ce6 by natural capture ability for Cu2+ ions. GLT21.T, the aptamer targeting lung cancer, was conjugated to the surface of the lipid nanocapsules. Iodixanol was loaded into the cavity of the lipid nanocapsule (64Cu@LCI-apt). In the nanostructure, the loading of iodixanol was sufficiently high, and the specific activity could be flexibly adjusted according to imaging requirements. The prepared 64Cu@LCI-apt achieves excellent radiolabeling efficiency, stability and effective targeting of lung tumor. In an early orthotopic lung cancer model, 64Cu@LCI-apt demonstrated the capabilities of sensitive PET imaging and enhanced contrast CT imaging to enable efficient high-quality PTE/CT imaging of tiny orthotopic lung tumor with a diameter of 500 μm. 64Cu@LCI-apt has great potential for early, sensitive, and accurate diagnosis of tumors through dual-mode PET/CT imaging.
Keywords: PET/CT imaging; dual modality; early diagnosis; lipid nanocapsules; orthotopic lung tumor.