Porphyrin Immobilized Nanographene Oxide for Enhanced and Targeted Photothermal Therapy of Brain Cancer

Brain cancer is a fatal disease that is difficult to treat because of poor targeting and low permeability of chemotherapeutic drugs through the blood brain barrier. In a comparison to current treatments, such as surgery followed by chemotherapy and/or radiotherapy, photothermal therapy is a remarkable noninvasive therapy developed in recent years. In this work, porphyrin immobilized nanographene oxide (PNG) was synthesized and bioconjugated with a peptide to achieve enhanced and targeted photothermal therapy for brain cancer. PNG was dispersed into the agar based artificial tissue model and demonstrated a photo-to-thermal conversion efficiency of 19.93% at a PNG concentration of only 0.5 wt %, with a heating rate of 0.6 degrees C/s at the beginning of irradiation. In comparison, 0.5 wt % graphene oxide (GO) indicated a photo-to-thermal conversion efficiency of 12.20% and a heating rate of 0.3 degrees C/s. To actively target brain tumor cells without harming healthy cells and tissues surrounding the laser path, a tripeptide L-arginyl-glycylL-aspartic (RGD) was further grafted to PNG. The photothermal therapy effects of PNG-RGD completely eliminated the tumor in vivo, indicating its excellent therapeutic effect for the treatment of brain cancer.