Evaluation of a nanocomposite of PEG-curcumin-gold nanoparticles as a near-infrared photothermal agent: an in vitro and animal model investigation.

Hyperthermia is a promising alternative modality for the conventional cancer treatments. Nanoparticle-mediated photothermal therapy (PTT) has been widely applied for hyperthermia cancer therapy by a near-infrared light irradiation. Some special nanoparticles can convert light energy into heat and destroy the tumor cells. Inspired from the photothermal efficacy of the gold nanoparticles, here we synthesized, characterized, and applied novel photothermal polyethylene glycol-curcumin-gold nanoparticles (PEG-Cur-Au NPs) in cancer PTT. The effect of PEG-Cur-Au NPs upon irradiation by an 808-nm laser on C540 (B16/F10) cell line as well as implanted (bearing) melanoma tumor in inbred C57 mice was investigated. In vitro temperature increment, cell viability evaluation, and histological analyses were performed. The results showed a dose-dependent cytotoxicity of PEG-Cur-Au NPs toward C540 (B16/F10) cell line at concentrations ≥ 25 μg mL-1 with an IC50 value of 42.7 μg mL-1 in dark (and with no toxicity for 10 μg mL-1). On the other hand, 808-nm laser irradiation alone (without using PEG-Cur-Au NPs) for 10 min induced killing effect on the C540 (B16/F10) cell line in a laser power-dependent manner at power density > 0.5 W cm-2 (no toxicity for 0.5 W cm-2). However, PPT using PEG-Cur-Au NPs was tremendously observed after laser illumination. Even under laser irradiation at a power density of 0.5 W cm-2 of PEG-Cur-Au NPs of concentrations < 10 μg mL-1, PTT of the cells was substantial. Histological analyses and volume measurements of the induced tumors in the mice revealed an appropriate control of the tumors upon PTT by PEG-Cur-Au NPs. Combination of PEG-Cur-Au NP administration and 808-nm diode laser irradiation destroyed the melanoma cancer cells in the animal model.