Combined therapeutics dependent on the synergistic effect between photothermal therapy (PTT) and chemotherapy have been anticipated to be the next generation of cancer treatment. For this purpose, a novel gold hydrosol was synthesized by a one-pot approach using poly (2-(dimethylamino) ethyl methacrylate-co- N-isopropylacrylamide-co- 2-vinylpyridine) P(DMAEMA-co-NIPAAM-co-VP) terpolymers as a reducing and stabilizing agent. The synthesized gold hydrosol was recoated by a novel carboxylic acid rich poly (N-isopropyl acrylamide-co-maleic anhydride-graft-citric acid) (PNIPAAm-co-PMA-g-CA) copolymer. Then the gold nanoparticles conjugated with Doxorubicin (DOX) and served as a smart photo synthesizer for chemo/photothermal therapy of MCF-7 breast cancer cells. The synthesized nanoparticles had mono-dispersed spherical morphology with a diameter below 30 nm. Our results from cellular uptake indicated that around 100% of the particles were uptake by MCF-7 cells in the first 3 h of exposure time. The temperature of nanocomposites considerably went up to 45 °C with 10 min exposure to near-infrared irradiation. As a striking result, a single round of PTT combined with a sub-therapeutic dose of DOX revealed a synergistic effect with an ability of robust anti-tumor response up to 99.99% (sum of the population of apoptotic and necrotic cells) demonstrated by Annexin-V, cell cycle and DAPI staining techniques. In conclusion, Near-infrared-mediated photothermal conversion exhibited high effectiveness of a combinational chemo-thermotherapy to treat cancer cells.
Keywords: Apoptosis; Combination therapy; Doxorubicin; Photothermal effect; Smart gold hydrosol.
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