Carbon-Encapsulated Iron Nanoparticles Seeking Integrins in Murine Glioma

Targeting integrin receptors for MRI represents a novel method in diagnosing glioblastoma. In the present study carbon-encapsulated iron nanoparticles to explore murine glioma tracking based upon specific direct targeting with monoclonal antibodies against the beta-3 subunit (CD61) of the integrin αVβ3 receptor are described.

The carbon arc discharge method was used to synthesize nanoparticles and amidation-type reaction were applied to attach monoclonal antibody (anti-CD61) with acidic group functionalized nanoparticles to lead two types of bioconjugates (Fe@C-CONH-anti-CD61 and Fe@C-(CH₂)₂-CONH-anti-CD61). The as-synthesized bioconjugates were tested on murine glioma cells (GL261) using MTT, LDH and calcein AM/propidium iodide assays. Relaxometry measurements were performed with a 1.5 T (63 MHz) MRI scanner using both GL261 cells and C57BL/6 mice bearing GL261 tumors.

The results showed that Fe@C-CONH-anti-CD61 and Fe@C-(CH₂)₂-CONH-anti-CD61 nanoparticles have higher binding affinity towards GL261 cells compared to pristine nanoparticles without antibodies. Studies evidenced that the antibody-decorated nanoparticles did not produce any severe cytotoxic effects on murine glioma cells. Preclinical MRI studies demonstrated that the Fe@C-(CH₂)₂-CONH-anti-CD61 nanoparticle-based construct specifically targeted murine glioma in animals.

The carbon-encapsulated iron nanoparticles functionalized with monoclonal antibodies recognizing the beta-3 subunit of the integrin αVβ3 receptor can be considered as a potential contrast agent for MRI-based tracking glioblastoma.