Development of novel nanoporphyrin biomaterials for NIR-II activated photothermal therapy against tumor in vivo

Photothermal therapy (PTT), a promising spatiotemporally controllable cancer treatment method, needs effective depth of laser irradiation to ensure the anticancer efficiency. Second near-infrared window (NIR-II) absorbing conjugated polymer (CP) nanomaterials are emerging candidates for a non-invasive treatment of cancer with considerations of safety. Herein, a new organic CP compound (Ppordpp) with the donor-acceptor structure of porphyrin and diketopyrrolopyrrole was synthesized, which showed efficient absorption extending in NIR-II and spontaneously self-assembled into NPs (∼190 nm), leading to emission quenching and facilitating nonradiative thermal generation. Photothermal conversion efficiency (PCE) of our Ppordpp NPs was up to 86.21 %, higher than most of reported PTT reagents. Under 940 nm (0.75 W/cm 2 ) laser irradiation for 10 min, the Ppordpp NPs showed dramatical PTT effects in vitro to kill 78 % 4T1 cancer cells with 40 μg/mL incubation, and in vivo to almost completely inhibition tumor growth by 200 μg/mL injection without obvious side effects. Our CP nanomaterials Ppordpp NPs with a D-A structure provide new alternatives for precise cancer through photothermal therapy with high PCE.