High specificity targeting and detection of human neuroblastoma using multifunctional anti-GD2 iron-oxide nanoparticles.

AIM: To develop biocompatible, tumor-specific multifunctional iron-oxide nanoconstructs targeting neuroblastoma, an aggressive pediatric malignancy. MATERIALS & METHODS: Clinical-grade humanized monoclonal antibody (hu14.18K322A), designed to target GD2 antigen on neuroblastoma with reduced nonspecific immune interactions, was conjugated to hydroxyethyl starch-coated iron-oxide nanoparticles. Targeting capability in vitro and in vivo was assessed by immunofluorescence, electron microscopy, analytical spectrophotometry, histochemistry and magnetic resonance R2* relaxometry. RESULTS: The biocompatible nanoconstructs demonstrated high tumor specificity in vitro and in vivo, and low background uptake in a mouse flank xenograft model. Specific accumulation in tumors enabled particle visualization and quantification by magnetic resonance R2* mapping. CONCLUSION: Our findings support the further development toward clinical application of this anti-GD2 iron-oxide nanoconstruct as diagnostic and therapeutic scaffold for neuroblastoma and potentially other GD2-positive malignancies.

Linker-free conjugation and specific cell targeting of antibody functionalized iron-oxide nanoparticles.

Specific targeting is a key step to realize the full potential of iron oxide nanoparticles in biomedical applications, especially tumor-associated diagnosis and therapy. Here, we developed anti-GD2 antibody conjugated iron oxide nanoparticles for highly efficient neuroblastoma cell targeting. The antibody conjugation was achieved through an easy, linker-free method based on catechol reactions. The targeting efficiency and specificity of the antibody-conjugated nanoparticles to GD2-positive neuroblastoma cells were confirmed by flow cytometry, fluorescence microscopy, Prussian blue staining and transmission electron microscopy. These detailed studies indicated that the receptor-recognition capability of the antibody was fully retained after conjugation and the conjugated nanoparticles quickly attached to GD2-positive cells within four hours. Interestingly, longer treatment (12 h) led the cell membrane-bound nanoparticles to be internalized into cytosol, either by directly penetrating the cell membrane or escaping from the endosomes. Last but importantly, the uniquely designed functional surfaces of the nanoparticles allow easy conjugation of other bioactive molecules.