Low-density lipoprotein (LDL) plays a central role in the development of atherosclerosis, making its detection critical for cardiovascular disease management. Radionuclide imaging of LDL offers distinct advantages over other modalities but remains limited by poor specificity and the need for long-lived isotopes. We present a click chemistry-based PET imaging strategy using gallium-68 (68Ga), a short-lived radionuclide, for the specific detection of LDL accumulation in atherosclerotic plaques. The approach relies on a two- step inverse electron-demand Diels−Alder reaction between trans-cyclooctene (TCO)-modified LDL and tetrazine-functionalized iron oxide nanoparticles radiolabeled with 68Ga. In vivo PET/CT imaging in LDL receptor-deficient (LDLr−/−) mice showed selective uptake of the nanoparticles in athero- sclerotic lesions, with minimal signal in wild-type controls. This method demonstrated high specificity and sensitivity, while reducing background signal and radiation exposure. Our results support the potential of this approach as a noninvasive and translatable platform for early diagnosis and risk assessment in cardiovascular disease.

The authors acknowledge financial support through the Spanish Ministry of Science and Innovation (PDC2022- 133493-100, RED2022-134299-T, PID2019-104059RB-100 and PID2024-155894OA-100), Comunidad de Madrid (P2022/BMD-7333) and Conexion Nanomedicina CSIC. J. P. acknowledges financial support from the Ramon y Cajal program (Grant No. RYC2023-043157-I) funded by the MCIN/AEI/10.13039/501100011033 and the ESF “Investing in your future”. We also acknowledge financial support from Ministerio de Economía, Industria y Competitividad (MEIC) with cofunding from the European Regional Development Fund (ERDF) [grants PI2019-108568RB-I00 to J.F.B., BES- 2016-076633 to P.N.]. The Centro Nacional de Investiga- ciones Cardiovasculares (CNIC) is supported by the Instituto de Salud Carlos III (ISCIII) and the Ministerio de Ciencia e Innovación (MICIN). The institute of Materials Science of Barcelona and the Pro CNIC Foundation are Severo Ochoa Center of Excellence in R&D (CEX2023-001263-S and CEX2020001041-S) funded by MCIN/AEI/10.13039/ 501100011033 and by FEDER, “A way of making Europe”.

Peer reviewed