Studies On Synergistic Tumor Therapy Based On Functional ZnO@PDA Core-shell Nanocomposite

In recent years,tumor has posed a hazard to people’s health and lives.Traditional treatments,such as chemotherapy,surgery and radiation therapy,still have some shortcomings.Therefore,it is urgent to develop new types of cancer therapy.The application of nanocomposites to cancer therapy has received much attention.The zinc oxide-polydopamine core-shell nanocomposite(ZnO@PDA)has merits of high photothermal conversion efficiency,facile preparation,great biocompatibility,and large entrapment capacity.At the same time,it can also be used as a nanocarrier to deliver drugs,thereby reducing the side effects caused by drugs.Therefore,the following studies based on ZnO@PDA nanocomposites are as follow:1.ZnO@PDA-DOX nanocomposite for chemo-photothermal synergistic therapyWe first synthesized ZnO@PDA core-shell nanocomposites by ultrasonic method.In this nanocomposite,ZnO was core and polydopamine(PDA)was the outer layer.Then the drug doxorubicin(DOX)was modified on the surface of the ZnO@PDA by electrostatic or π-π stacking,developing a near-infrared light-controlled chemo-photothermal synergistic therapeutic system(ZnO@PDA-DOX).Under 780 nm laser irradiation,ZnO@PDA-DOX could convert light energy into heat and result in an increase in local temperature of cells for photothermal therapy.Additionally,high temperatures could also cause the release of DOX for chemotherapy.The cell viability was decreased to 45.8% under the chemo-photothermal synergistic therapy.2.ZnO@Ce6-PDA nanocomposite for photodynamic-photothermal synergistic therapyBased on the previous study,we have further constructed nanocomposites that could be used in photodynamic-photothermal synergistic therapy.This nanocomposite(ZnO@Ce6-PDA)was composed of a core of ZnO,an interlayer of photosensitizer chlorin e6(Ce6)and an outer layer of PDA.Due to the existence of Ce6,the ZnO@Ce6-PDA could efficiently generate singlet oxygen under 660 nm laser irradiation.Moreover,the ZnO@Ce6-PDA could serve as a photothermal agent because of the excellent photothermal conversion efficiency of the coating layer of PDA under the irradiation with 780 nm.The cell viability was reduced to 22.1% upon the photodynamic-photothermal synergistic therapy.