Highly Efficient Homologous Targeting Magnetic Resonance Imaging Probe for Enhanced T1 Contrast Imaging of Triple-Negative Breast Cancer by Deactivated Tumor Cell-Loaded Manganese Carbonate

The highly efficient, tumor-specific targeting capability of contrast agents enables accurate cancer diagnosis via magnetic resonance imaging (MRI). In this study, a homologous targeting T1 MRI probe with pH-responsive properties was developed for precise diagnosis of triple-negative breast cancer. MnCO3 nanoclusters, as a T1 MRI contrast agent, respond to the acidic tumor microenvironment by releasing paramagnetic Mn2+ ions. Subsequently, deactivated 4T1 cells, treated by freezing to preserve their cell membrane, were employed as biomimetic carriers for MnCO3 (d4T1@Mn), serving as the homologous targeting T1 MRI probe. Compared to traditional cancer cell membrane-camouflaged nanoplatforms (Cm@Mn) and Mn-DPDP, this T1 MRI probe, owing to its intact cell membrane structure and superior homologous targeting capability, enhances contrast agent accumulation at the tumor site, intensifies T1-weighted MR signals in the tumor region, significantly improves the signal-to-noise ratio and tumor-to-muscle ratio, and provides an extended optimal imaging window, thereby enabling precise diagnosis of triple-negative breast cancer. In vivo studies further demonstrated that systemic administration of the MRI probe did not induce blood or tissue damage, confirming its excellent biocompatibility. In conclusion, this approach successfully introduces an effective tumor-specific T1 MRI probe, improving tumor diagnosis accuracy in MRI.