A new photothermal nano-agent was obtained by the coprecipitation of 2,5-Bis(2,5-bis(2-thienyl)-N-dodecyl pyrrole) thieno[3,4-b][1,2,5]
thiadiazole (
TPT-TT) and a biodegradable amphiphilic block copolymer, methoxypoly(ethylene glycol)2K-block-poly(D,L-lactide)2K (mPEG2K-PDLLA2K).
TPT-TT, a donor-acceptor-donor (D-A-D) type small molecule, with bis(2-thienyl)-N-alkylpyrrole (
TPT) as the donor and thieno[3,4-b]
thiadiazole (TT) as the acceptor was a strong near infrared (NIR) absorber, which could convert the absorbed light energy into heat. The formation of
TPT-TT nanoparticles (
TPT-NPs), which possessed high stability in water, was confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM).
TPT-NPs showed high photothermal conversion efficiency (32%) and excellent photostability and heating reproducibility. The photostability of
TPT-TT NPs was much better than that of
indocyanine green (ICG), a federal drug administration (FDA) approved NIR
dye. Besides,
TPT-TT NPs exhibited significant photothermal
therapeutic effect toward human cervical
carcinoma (HeLa) and human liver
hepatocellular carcinoma (HepG2) cells, while no appreciable dark cytotoxicity was observed. These results highlight the potential of
TPT-TT NPs as an effective photothermal agent for
cancer therapy.