Preparation Of Carbon Encapsulated Gold Nanocapsule And Its Application In Cancer Cell Imaging And Therapy

Cancer also known as malignant tumor is one of the major diseases that threaten human health. In recent years, a sharp increase in the incidence of cancer with the survival of the deterioration of the environment. Early detection and prompt treatment are the keys to treating cancer. Although in recent years, treatment methods and drug development is innovation, the most effective treatment is still the traditional methods of surgery, chemotherapy and radiotherapy. Especially chemotherapy is considered to be the most promising way to cure cancer. However, traditional chemotherapy is difficult to achieve the desired therapeutic effect because targeted drug delivery with poor results and tumor resistance lead to strong side effects, which cause serious damage to the body. Therefore, drug nanocarriers designed with good biocompatibility, high stability, good targeting and easy modification have become a hotspot for cancer research. The combination of anti-cancer drugs and nanocarriers has important significance for early diagnosis and treatment of cancer.In recent years, multi-functional nanomaterials have attracted widespread attention due to their setting security, multi-therapy and imaging in a body in the diagnosis and treatment of cancer. Gold nanomaterials were widely used in biosensor, photothermal treatment, immunoassays and vivo imaging owing to their excellent optical and thermal properties. Carbon nanomaterials as a kind of common nanomaterials, have the advantage of larger surface area, good biocompatibility, strong adsorption capacity, more surface functional groups and simple preparation process. The core-shell nanomaterials are formed by one nanomaterial wrapping up another nanomaterial through chemical or other interaction. The shell can effectively change functional groups, surface charge and reaction characteristics of the core and improve its stability and dispersion, which can make core-shell nanoparticals become ideal carriers in drug delivery, gene therapy and medical imaging.We synthesized AuNR@Carbon nanocapsules by hydrothermal method and AuNR@Graphene nanocapsules by chemical vapor deposition method(CVD). We also characterized the microstructure of these nanomaterials using a variety of analytical tools and developed their applications in biological detection and treatment of cancer. The main contents are as follows:(1)Synthesis and characterization of AuNR@Carbons and AuNR@Graphenes. We used CTAB as a template to synthesize AuNRs with aspect ratio of about 3.5 by seed growth method. The carbon shell was formed on the surface of AuNR b y hydrothermal method and the graphene shell was formed on the surface of AuNR by CVD method, which made AuNRs have some unique properties. We also characterized the structure of these nanomaterials using SEM, TEM, FTIR, UV-vis and Raman spectrum. The results showed that AuNR@Carbon nanocapsules and AuNR@Graphene nanocapsules have potential applications in cancer imaging and targeted therapy.(2)Application of AuNR@Carbons in cancer imaging. AuNR@Carbon nanocapsules are with fluorescent properties whose maximum excitation wavelength is 405 nm. The source of the fluorescence is the formation of large conjugated aromatic structure during hydrothermal carbonization of glucose. Therefore, AuNR@Carbon nanocapsules can be used for fluorescence imaging of cancer cells. Increasing the thickness of carbon shell can effectively reduce the fluorescence quenching of AuNRs. At the same time, AuNR@Carbon nanocapsules can be used for two-photon fluorescence imaging of cancer cells due to their unique two-photon fluorescence properties.(3)Application of AuNR@Carbons in the treatment of cancer. Firstly, owing to their high surface areas, the AuNR@Carbo n nanocapsules are able to load DOX through ?-? stacking or electrostatic interaction to form AuNR@Carbon-DOX. AuNR@Carbon-DOX will slowly release DOX to treat cancer when they are irradiated with a laser after entering the cells. Secondly, AuNRs with LSPR effect and photothermal effect can implement photothermal therapy for cancer during chemotherapy. Chemotherapy combined with hyperthermia is possible to achieve better therapeutic effect. Thirdly, due to different fluorescence properties of AuNR@Carbons and DOX, they can simultaneously localize and monitor drug and carrier by CLSM. Fourthly, the aptamer AS1411 is able to specificly recognize the overexpressing nucleolin on the surface of cancer cells. AuNR@Carbon-DOX connected with AS1411 will improve phagocytic efficiency of nanoparticles to achieve targeted therapy of cancer.