I6P7 peptide modified superparamagnetic iron oxide nanoparticles for magnetic resonance imaging detection of low-grade brain gliomas.

Glioma, the most severe primary brain malignancy, has very low survival rates and a high level of recurrence. Nowadays, conventional treatments for these patients are suffering a similar plight owing to the distinctive features of the malignant gliomas, for example chemotherapy is limited by the blood-brain barrier while surgery and radiation therapy are affected by the unclear boundaries of tumor from normal tissue. In the present study, a novel superparamagnetic iron oxide (SPIO) nanoprobe for enhanced T2-weighted magnetic resonance imaging (MRI) was developed. A frequently used MRI probe, SPIO nanoparticles, was coated with a silica outer layer and for the first time was covalently modified with interleukin-6 receptor targeting peptides (I6P7) to promote transportation through the blood-brain barrier and recognition of low-grade gliomas. The efficiency of transcytosis across the blood-brain barrier was examined in vitro using a transwell invasion model and in vivo in nude mice with orthotopic low-grade gliomas. The targeting nanoprobe showed significant MRI enhancement and has potential for use in the diagnosis of low-grade gliomas.