Preparation Of Mesoporous Silica-based Nanocomposites With Sandwich Structure And Its Application In Cancer Treatment

In this paper,silica coated graphene oxide was prepared by oil-water two-phase separation method,and then the surfactant template was removed by ion exchange method and reduced by HI solution.Finally,a sandwich-structured mesoporous silica coated graphene oxide（r GO@m Si O₂）nanosheets with photothermal and drug-loading functions was successfully synthesized.Inspired by the synergistic treatment mode,this paper synthesized r GO@m Si O₂-NO based on the core@silica shell structure.The material is prepared by coating the reduced graphene oxide core with a mesoporous silica shell.The silica provides a reservoir for the NO donor（tert-butyl nitrite）,and the core r GO produces a thermal shock under the irradiation of the near-infrared laser.Therefore,the synergistic treatment mode of generating heat from the light-triggered core r GO and generating NO from the heat-triggered NO donor can be realized.In this paper,a core@silica shell structure r GO@m Si O₂-NO/DOX@UCNP nanocomposite that responds to near-infrared light and carries the chemotherapeutic drug doxorubicin（DOX）was designed.Firstly,r GO@m Si O₂-NO was prepared.Then,DOX drugs were loaded into the pores of mesoporous silica through physical adsorption,and UCNP was connected to the surface of silica as a pore-sealing agent by amidation reaction to prevent the leakage of DOX drugs.Finally,r GO@m Si O₂-NO/DOX@UCNP nanocomposite was successfully synthesized,which integrates chemotherapy,gas treatment and photothermal treatment.The results showed that under the irradiation of near-infrared laser,the photothermal-sensitive azo bond on the surface of r GO@m Si O₂-NO/DOX@UCNP broke,UCNP fell off,and DOX drug was released.At the same time,the NO donor will also be subjected to thermal stimulation,thereby escaping NO molecules to achieve gas therapy.In addition,in vitro cytotoxicity experiments showed that r GO@m Si O2-NO/DOX@UCNP not only had excellent near-infrared-induced photothermal properties,but also co-delivered NO and DOX drugs to inhibit tumor cell growth.It has the advantages of remote operation and non-invasive intervention in cancer treatment.