Polydopamine nanomotors loaded indocyanine green and ferric ion for photothermal and photodynamic synergistic therapy of tumor

The limited penetration depth of nanodrugs in the tumor and the severe hypoxia inside the tumor signif-icantly reduce the efficacy of photothermal-photodynamic synergistic therapy (PTT-PDT). Here, we syn-thesized a methoxypolyethylene glycol amine (mPEG-NH2)-modified walnut-shaped polydopamine nanomotor (PDA-PEG) driven by near-infrared light (NIR). At the same time, it also loaded the photosen-sitizer indocyanine green (ICG) via electrostatic/hydrophobic interactions and chelated with ferric ion (Fe3+). Under the irradiation of NIR, the asymmetry of PDA-PEG morphology led to the asymmetry of local photothermal effects and the formation of thermal gradient, which can make the nanomotor move auton-omously. This ability of autonomous movement was proved to be used to improve the permeability of the nanomotor in three-dimensional (3D) tumor sphere. Fe3+ can catalyze endogenous hydrogen peroxide to produce oxygen, so as to overcome the hypoxia of tumor microenvironment and thereby generate more singlet oxygen to kill tumor cells. Animal experiments in vivo confirmed that the nanomotors had a good PTT-PDT synergistic treatment effect. The introduction of nanomotor technology has brought new ideas for cancer optical therapy. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

A walnut-shaped polydopamine nanomotor (PDA-PEG) modified with methoxypolyethylene glycol amine (mPEG-NH2) was synthesized. This nanomotor is driven by near-infrared light (NIR) and loaded with the photosensitizer indocyanine green (ICG) and ferric ion (Fe3+). The asymmetry of PDA-PEG morphology leads to autonomous movement, improving the permeability of the nanomotor in a 3D tumor sphere. Fe3+ catalyzes the production of oxygen, overcoming tumor microenvironment hypoxia and generating more singlet oxygen to kill tumor cells. Animal experiments confirmed the good synergistic treatment effect of the nanomotors in photothermal-photodynamic therapy (PTT-PDT).