Application Of Polydopamine Nanomotors In Cancer Therapy

Light stimulation therapy,which includes photothermal therapy and photodynamic therapy,is an emerging cancer treatment method.It has attracted wide attention because of its low cost,good specificity and less side effects on normal tissues.Based on this,we designed and synthesized walnut-shaped polydopamine nanomotors with good biocompatibility,which were loaded with chemical drugs and photosensitizers respectively for photothermal-chemotherapy and photothermal-photodynamic therapy respectively.The details are as follows:1.Preparation and performance study of polydopamine nanomotor photothermal therapeutic agent.For the first time,we explored the photothermal therapeutic effect of the walnut-shaped polydopamine nanomotor,and modified it with methoxypolyethylene glycol amine to improve its water solubility and biocompatibility.Walnut-shaped polydopamine has good biocompatibility and high light-to-heat conversion efficiency（40%）.Under the irradiation of near infrared（NIR）laser,the asymmetry of the walnut morphology of the nanoparticles leads to the asymmetry of the local photothermal effect and forms a thermal gradient.Therefore,the nanoparticles generate thermophoretic phenomenon,move from high temperature to low temperature,and can overcome Brownian motion.Therefore,under the NIR laser power of 2 W/cm²,the autonomous motion generated can actively drive the movement of the nanomotor,which improves the penetration ability of the nanomaterial.Experimental results show that walnut-shaped polydopamine has a good photothermal treatment effect.It provides a new photothermal therapy platform for polydopamine with other shapes.2.Polydopamine nanomotor loaded with chemical drug doxorubicin hydrochloride for photothermal-chemotherapy synergistic therapy.Photothermal-chemotherapy is a promising cancer treatment strategy,but its development is hindered by the long-term safety of the carrier and the permeability and release of drugs.In this chapter,we loaded the chemotherapy drug doxorubicin hydrochloride（DOX）on the basis of fuel-free,NIR-driven walnut-shaped polydopamine nanomotor.DOX is released under NIR and the p H of the cell environment,and the degradation of polydopamine itself also promotes the release of DOX.The exercise ability of the nanomotor can improve the permeability of the drug and the release ability of the drug,and greatly improve the therapeutic effect.The 3D tumor ball treatment results show that the exercise ability of the polydopamine nanomotor improves the permeability of the loaded DOX in the tumor ball.At the same time,photothermal-chemotherapy has shown good performance in killing cancer cells and eliminating tumors.3.Polydopamine combined with photosensitizer indocyanine green and Fe³⁺to overcome hypoxia photothermal photodynamic synergistic therapy.Indocyanine green（ICG）can activate the surrounding oxygen molecules to produce cytotoxic singlet oxygen under NIR,which can kill tumor cells.However,because the tumor is a hypoxic environment,it is necessary to overcome the problem of hypoxic in the tumor environment.Based on this,we prepared a multifunctional composite nanomaterial.By modifying the photosensitizer ICG on the surface of polydopamine,chelating Fe³⁺catalyzed the generation of oxygen from hydrogen peroxide in tumor cells to solve the problem of hypoxia in the tumor microenvironment.The composite nanomaterial exhibits low cytotoxicity,and it has a good photothermal and photodynamic synergy therapy effect,and can kill tumor cells in vitro.Therefore,the constructed multifunctional nanomaterial has a strong application prospect in the collaborative treatment of tumors.