Chiral Iron Oxide Supraparticles Enable Enantiomer-Dependent Tumor-Targeted Magnetic Resonance Imaging

The chemical, physical and biological effects of chiral nanomaterials have inspired general interest and demonstrated important advantages in fundamental science. Here, chiral iron oxide supraparticles (Fe₃ O₄ SPs) modified by chiral penicillamine (Pen) molecules with g-factor of ≈2 × 10^-3 at 415 nm are fabricated, and these SPs act as high-quality magnetic resonance imaging (MRI) contrast agents. Therein, the transverse relaxation efficiency and T₂ -MRI results demonstrated chiral Fe₃ O₄ SPs have a r₂ relaxivity of 157.39 ± 2.34 mM^-1 ·S^-1 for D-Fe₃ O₄ SPs and 136.21 ± 1.26 mM^-1 ·S^-1 for L-Fe₃ O₄ SPs due to enhanced electronic transition dipole moment for D-Fe₃ O₄ SPs compared with L-Fe₃ O₄ SPs. The in vivo MRI results show that D-Fe₃ O₄ SPs exhibit two-fold lower contrast ratio than L-Fe₃ O₄ SPs, which enhances targeted enrichment in tumor tissue, such as prostate cancer, melanoma and brain glioma tumors. Notably, it is found that D-Fe₃ O₄ SPs have 7.7-fold higher affinity for the tumor cell surface receptor cluster-of-differentiation 47 (CD47) than L-Fe₃ O₄ SPs. These findings uncover that chiral Fe₃ O₄ SPs act as a highly effective MRI contrast agent for targeting and imaging broad tumors, thus accelerating the practical application of chiral nanomaterials and deepening the understanding of chirality in biological and non-biological environments.