RGD peptide-conjugated polydopamine nanoparticles loaded with doxorubicin for combined chemotherapy and photothermal therapy in thyroid cancer

To construct polydopamine (PDA)-based nanoparticles (NPs) for combined chemotherapy (CT) and photothermal therapy (PTT) of thyroid tumors by conjugating doxorubicin (DOX) via Schiff base reaction and decorating with RGD peptide.

PDA NPs were synthesized using dopamine hydrochloride (DA) as the raw material and reacted with DOX-PEG-NH₂ to obtain PDA-DOX NPs. Subsequently, RGD peptide was coupled with PDA-DOX NPs for modification. Their size, charge, and shape were characterized using DLS and SEM. The assembly of DOX was verified by ultraviolet–visible spectroscopy (UV–Vis), and the release efficiency of DOX under different pH conditions was calculated. The antitumor effect of RGD@PDA-DOX was validated in KTC-1 cells and tumor-bearing nude mice.

The prepared RGD@PDA-DOX exhibited excellent dispersion, stability, and biocompatibility. PDA-DOX possessed superior photothermal conversion efficiency, capable of rapidly elevating the solution temperature within 5 min. In vitro studies revealed that the inhibitory rate of RGD@PDA-DOX combined with 808 nm laser on KTC-1 cells reached 92% (p < 0.05). In vivo experiments demonstrated that RGD@PDA-DOX exhibits no cytotoxicity. The modification with RGD peptides enables RGD@PDA-DOX to target tumor regions and accumulate over an extended period. Additionally, RGD@PDA-DOX, when combined with an 808 nm laser, significantly inhibits tumor growth.

RGD@PDA-DOX can effectively accumulate in tumor regions and demonstrates excellent anti-tumor efficacy. It may serve as a feasible approach for the effective treatment of thyroid tumors, providing further evidence and data for clinical translation.