No abstract

Photothermal therapy (PTT) holds great promise for noninvasive cancer treatment. To fulfill this goal, highly effective and low-risk photothermal agents have been intensively explored. Here, we present a new PTT material based on conjugated polymer dots (Pdots) that exhibit strong near-infrared (NIR) absorption and high photostability. The Pdots result in a thermal response upon illumination with a NIR laser, leading to a high photothermal conversion efficiency of 65%. Thus, the photothermal ablation of cancer cells using the Pdots both in vitro and in vivo can be achieved, highlighting the potential of Pdots as a nanoplatform for clinical therapy. They also open up a new avenue to develop new photothermal therapeutic materials.

Preparation of Au/PDMS films: PDMS films were prepared from Sylgard 184 Silicone Elastomer Kit (Dow Inc.). A mixture of precursor and crosslinker at 10:1 ratio was spin coated on a fluorinated silicon wafer at 800 rpm for 60 s, and cured 60 o C for 5 h. The prepared PDMS films were around 70 μm thick. Au nanolayers were deposited by a vacuum thermal evaporator (Nano 36, Kurt J. Lesker) under 2×10 -6 Torr with a deposition rate of 0.3 Å/s. The Au source was purchased from Kurt J. Lesker and the purity was 99.99%. The deposition time was controlled to get 80 nm thick gold layers.Synthesis of dopamine methacrylamide (DMA) monomer: DMA monomer was synthesized according to the previously reported method. [S1] 10 g of sodium tetraborate and 4 g of sodium bicarbonate were dissolved in 100 mL deionized water and bubbled with nitrogen for 20 min.With continuous nitrogen flow, 5 g of dopamine hydrochloride (26.4 mmol) was dissolved in the solution. Then 5 mL of methacrylate anhydride (94 % purity, 29.1 mmol) in 20 ml THF was added dropwise, during this process the pH was kept above 8 with the addition of 1 M sodium hydroxide. The mixture was stirred overnight at room temperature. The reaction mixture was washed twice with 50 mL ethyl acetate, and then the pH of the aqueous solution was changed to less than 2 and extracted with 50 mL of ethyl acetate three times. The ethyl acetate layers were combined and dried over sodium sulfate, evaporated to reduce to around 30