MRI tumor imaging by click chemistry using Gd(iii)-DOTA-DBCO and Ac₄ManNAz

Magnetic resonance imaging (MRI) is an important diagnostic tool widely used in clinical practice. It does not involve harmful ionizing radiation, allowing for more frequent or long-term imaging. However, MRI suffers from limited sensitivity, and contrast agents are often required to enhance signal intensity and image contrast. In particular, tumors cannot always be clearly distinguished from surrounding tissues. Therefore, one potential strategy to improve MRI for cancer diagnosis is to enable tumor-specific detection. In this study, we synthesized a novel MRI contrast agent by conjugating a gadolinium(iii)-DOTA complex with dibenzocyclooctyne (DBCO). An azide-modified mannosamine derivative was employed for metabolic glycoengineering, enabling the expression of chemical tags on cancer cell surfaces. These tags undergo a bioorthogonal click reaction with the functionalized gadolinium(iii)-DOTA complex, facilitating rapid and sensitive enhancement of MRI contrast for imaging of cancer cells both in vitro and in vivo.