Biosynthetic molecular imaging probe for tumor-targeted dual-modal fluorescence/magnetic resonance imaging

Molecular imaging enables noninvasive visualization of cancer-related biological processes for tumor diagnostics; engineering molecular probes for accurate and efficient tumor imaging remains challenge. Herein, by using a biosynthetic strategy, we prepared a tumor-targeted fluorescence/magnetic resonance protein-based probe for dual-modal imaging. The probe was biosynthesized by the fusion of targeting peptide (RGD) with fluorescence protein (RFP) and a small peptide (LBT) that had strong affinity with Gd³⁺. The probe showed excellent RGD-mediated tumor targeting and stable infrared emission, enabling sensitive tumor-specific imaging. Moreover, efficient T₁-weighted magnetic resonance imaging was observed both in vitro and at tumor sites, facilitating high spatial resolution tumor imaging. The simultaneous dual-modal imaging provided more complementary information than each imaging modality. Our work demonstrates the capability of biosynthetic strategy to engineer molecular imaging probes for tumor-targeted multimodal bioimaging, and the probes can be customized to precisely localize and monitor other types of diseases.