Tumor metastasis accounts for the major portion of cancer-related deaths. Magnetic resonance imaging (MRI) is a valuable
imaging modality for tumor diagnosis in clinical applications, offering detailed soft tissue images with excellent spatial resolution
and good biosafety. However, the low sensitivity and the lack of specificity to disease sites limit the application of MRI contrast
agents in early and precise detection of small primary and metastatic cancers. Therefore, there is an urgent need for innovative
MRI contrast agents with enhanced relaxivity, target ability, and pharmacokinetics to improve imaging sensitivity and widen
the detection window in the meantime. Here, we reported a dual-targeting pr... More
Tumor metastasis accounts for the major portion of cancer-related deaths. Magnetic resonance imaging (MRI) is a valuable
imaging modality for tumor diagnosis in clinical applications, offering detailed soft tissue images with excellent spatial resolution
and good biosafety. However, the low sensitivity and the lack of specificity to disease sites limit the application of MRI contrast
agents in early and precise detection of small primary and metastatic cancers. Therefore, there is an urgent need for innovative
MRI contrast agents with enhanced relaxivity, target ability, and pharmacokinetics to improve imaging sensitivity and widen
the detection window in the meantime. Here, we reported a dual-targeting protein MRI contrast agent (EPR-DTPA-Gd) fused
by a nanobody against epidermal growth factor receptor 1 (EGFR), integrin αvβ3-binding cyclic nonapeptide, and elastin-like
polypeptide. We found that this protein contrast agent exhibited high sensitivity and specificity for the tumor overexpressed EGFR
and integrin αvβ3 in MRI. Furthermore, EPR-DTPA-Gd had high longitudinal relaxation rate (r1) (68.76 mM−1 s−1 per molecule)
and an improved pharmacokinetics behavior for tumor imaging. Using T1-weighted imaging, EPR-DTPA-Gd successfully detected
a series of early metastases with the smallest 0.012 mm2 (213 µm × 58 µm) in a liver metastasis model of human cervical carcinoma
HeLa cells, which cannot be detected by the clinically approved T1-weighted contrast agent. The heightened detection sensitivity
intrinsic to EPR-DTPA-Gd facilitates precise imaging of tumor lesions, supporting sophisticated image-guided interventions and
early management in high-risk patient cohorts.