Lectin-conjugated Fe2O3@Au core@Shell nanoparticles as dual mode contrast agents for in vivo detection of tumor.

Here, we report the covalent conjugation of lectin on Fe2O3@Au core@shell nanoparticle (lectin-Fe2O3@Au NP) for T2-weighted magnetic resonance (MR) and X-ray computed tomography (CT) dual-modality imaging. The lectin-Fe2O3@Au NPs are prepared by coupling lectins to the Fe2O3@Au NP surfaces through bifunctional PEG NHS ester disulfide (NHS-PEG-S-S-PEG-NHS) linkers. After the nonspecific adsorption sites on the nanoparticle surface are blocked by thiolated PEG (PEG-SH), the lectin-Fe2O3@Au NPs exhibit excellent stability in biological medium and inappreciable cytotoxicity. A series of in vitro and in vivo experiments were then carried out for evaluating the capabilities of three selected lectin (ConA, RCA and WGA)-Fe2O3@Au NPs. The results revealed that the lectin-Fe2O3@Au NPs had a capacity not only for dual mode MR and CT imaging in vitro but also for MR and CT imaging of colorectal cancer in vivo. The experimental results also suggest that lectin could be used as tumor targeting ligand for synthesizing nanoparticle-based contrast agents.