Synthesis Of Graphite Carbon Nitride Quantum Dot Nanocomposite And Its Application In Cancer Imaging, Controlled Drug Release

Cancer has became one of the major threats to human health,and the methods of cancer treatment are increased and diversified nowadays.Chemotherapy is the most commonly used treatment for many different kinds of cancers,but its efficacy has been limited due to its toxic side effects.Photodynamic therapy has attracted enormous attention with its unique advantage.Additionally,using combinate method of treatment is easier to achieve the desired therapeutic effect than simply using one single method.Combining with the development of nanomaterials,it is possible to develop a safe nanocarrier for synergistic therapy.In this paper,mesoporous silica and manganese dioxide nanoparticles were used as carriers,and graphitic carbon nitride quantum dots were used as photosensitizer.we developed a series of nanocarriers for cancer imaging and treating.It is mainly divided into the following three parts:1.Sulfur doped graphitic carbon nitride quantum dots with efficient fluorescent property and their application for cell imagingIn this experiment,S-g-C₃N₄ was prepared by using dicyandiamide and thiourea,and S-g-C₃N₄ quantum dots were obtained by ultrasonication..The experimental results showed that the prepared S-g-C₃N₄ quantum dots with an average size of 2.0 nm were successfully prepared.the fluorescent intensity is greatly increased due to the sonication of bulk S-g-C₃N₄into quantum dots.S-g-C₃N₄ quantum dots not only show a blue color for cell imaging,but also have a bright green color.S-g-C₃N₄ quantum dot is a promising candidate for bioimaging benefiting from the efficient fluorescent property,good biocompatibility,and low toxicity.2.Graphitic carbon nitride quantum dots capped mesoporous silica nanocomposite as pH-responsive drug nanocarriers for imaging and therapy of cancer cellOn the basis of the above experiments,graphite carbon nitride quantum dots were further prepared,and the nanocarrier combining chemotherapy and photodynamic therapy was prepared by blocking the aminated mesoporous silica of drug-loaded doxorubicin with graphitic carbon nitride quantum dots as the sealing material..Under the irradiation of visible light,graphite carbon nitride quantum dots can generate singlet oxygen for photodynamic therapy,and in the acidic environment,the graphite carbon nitride quantum dots will be protonated and detach from the aminated mesoporous silica,releasing doxorubicin wich can effectively killing the cells.Cytotoxicity experiments demonstrated that the combination treatment of chemotherapy and photodynamic therapy kills cancer cells more efficiently.3.Graphitic carbon nitride quantum dots-manganese dioxide nanocomposite as Redox-responsive drug nanocarriers for imaging and therapy of cancer cellIn this experiment,graphitic carbon nitride quantum dots–manganese dioxide nanocomposites were developed through in situ synthesis of manganese dioxide nanoparticles in graphitic carbon nitride quantum dots colloid solution.Chemotherapy and photodynamic therapy were conbined to kill cancer cells again in this case.The manganese dioxide nanoparticles on the nanocarriers can be reduced by glutathione to release graphitic carbon nitride quantum dots,and drug-loaded doxorubicin on the graphitic carbon nitride quantum dots can also be released.Cytotoxicity experiments demonstrated that the combination treatment of chemotherapy and photodynamic therapy kills cells more efficiently.