SURG-07. Plasmonic gold nanostars to increase the efficiency and specificity of laser interstitial thermal therapy (LITT) in the treatment of brain tumors

Abstract

Abstract Introduction Laser interstitial thermal therapy (LITT) is an effective minimally-invasive treatment option for intracranial tumors. Our group produced plasmonics-active gold nanostars (GNS) designed to preferentially accumulate within intracranial tumors and amplify the ablative capacity of LITT while better conforming to tumor boundaries and protecting surrounding tissue. Materials and Methods: The 12nm GNS were synthesized using reduced HAuCl4 with Na3C6H5O7 seeds, mixed with AgNO3, C6H8O6, and HAuCL4, and coated with polyethylene glycol then functionalized with methoxy PEG thiol. CT-2A glioma cells were intracranially implanted into mice, followed 18 days later by IV injection of GNS. PET-CT was performed at 10-minutes, 24-, and 72-hours post-GNS administration, with autoradiography (AR) and histopathology (HP) on sacrifice after the last scan. To test the impact of GNS on LITT coverage capacity in appropriately sized ex vivo models, we utilized agarose gel-based phantoms incorporating control and GNS-infused central “tumors” in multiple shapes. LITT was administered with the NeuroBlate System. Results In vivo, GNS preferentially accumulated within intracranial tumors on PET-CT at the 24- and 72-hour timepoints. AR and HP confirmed high GNS accumulation within tumor. Ex vivo, in cuboid tumor phantoms, the GNS-infused phantom heated 5.5x faster than the control, rising 0.49°C per minute compared to 0.09°C. In a split-cylinder tumor phantom with half containing GNS, the GNS-infused border heated 2x faster and the surrounding area was exposed to 30% lower temperatures. In a GNS-infused star-shaped phantom, the heat spread contoured along phantom boundaries. Conclusion Our results provide evidence for use of GNS to improve the specificity, efficiency, and potentially safety of LITT. The in vivo data support selective accumulation within intracranial tumors, and the GNS-infused phantom experiments demonstrate increased rates of heating within the tumor model, heat contouring to tumor borders, and decreased heating of surrounding regions representing normal structures.