Semiconducting polymer nanotheranostics for NIR-II/Photoacoustic imaging-guided photothermal initiated nitric oxide/photothermal therapy

Gasotransmitters with their cytotoxicity in high concentration have become the focus of attention. For such concentration depended therapy, how to effectively deliver gases and precisely control gases release to the lesion as well as combine them with other therapy to achieve precise therapeutics is still a big challenge. Herein, we realize single near-infrared (NIR) laser-initiated nitric oxide (NO) therapy/photothermal therapy (PTT) using semiconducting polymer nanoparticles (SPNs, PFTDPP) combing s-nitrosothiol groups (the NO donor, SNAP). By the good photothermal conversion effect of SPNs, NIR laser energy can be spatio-temporally controlled to convert into heat to decompose s-nitrosothiol. Meanwhile, considering the accompanied PTT produced by photothermal, we can easily and precisely conduct a dual therapy (NO therapy/PTT) under single NIR laser irradiation. Additionally, semiconducting polymer with its structural modifiability and spectral adjustability can provide a second NIR window & photoacoustic (NIR II/PA) imaging for guiding photothermal initiated NO/photothermal therapy. PFTDPP showed a high photothermal conversion efficiency of 48% and good dual-mode imaging signals (NIR-II/photoacoustic). Cellular test illustrated that NO combined photothermal presented more prominent cytotoxicity than any one of them individually. As the tumor pinpointed in vivo by dual-mode imaging (NIR II/PA), this nanotheranostics provided a tumor inhibition of 77%. Consequently, such phototheranostics produced a new design thought for effectively deliver and precisely controlled release of drugs for oncology. And also, it expanded the application range of gasotransmitters combined therapy that shall have a promising application foreground.