Preparation Of Controlled Drug Release System And Its Biological Effect Based On Nanodiamond-methotreate

Cancer has almost become the first killer to human life, while its treatment is still facing many challenges currently. At present, the traditional methods of clinical cancer treatment, such as surgery, radiotherapy and chemotherapy, could kill tumor cells. However, these can cause tremendous side effects to the patients. So the study on anti-cancer drugs with efficiency and low toxicity is imminent. With the rapid development of innovative pharmaceutical and technology, the drug delivery system based on the nanoparticles provides a new way for it. The nanocarriers of current research mainly include carbon nanotubes, nanospheres, nanodiamond and liposomes, in which the nanodiamond because of its excellent photochemical properties, good biocompatibility, low toxicity and easy surface modification becomes focus at present.In the work, the ND-PEG-GLY-MTX nanomedicine was synthesized using nanodiamond (ND) as a carrier, chemotherapy drug Methotrexate (MTX) as the model drug, PEG-diamine (H2N-PEG-NH2) and glycidol (GLY) as the cross-linking agent. The interaction between the nanomedicine and HeLa cells was studied. In addition, using the tumor-bearing mice as animal models, the antitumor effects both ND-DOX and ND-PEG-FA-DOX nanomedicine in vivo were displayed. The main contents are as follows:1. The MTX was loaded onto the surface of nanodiamond through the ester bond, in which using nanodiamonds as the carrier, H2N-PEG-NH2 and GLY as the bridge. The complex was characterized by transmission electron microscopy, infrared spectroscopy and laser scattering particle analyzer, the coupled amount of MTX is 135 μg/mg on the surface of ND-PEG-GLY by UV-visible spectrophotometry. In addition, the drug release behavior of ND-PEG-GLY-MTX was studied, and the results showed that the cumulative release amount was the most in the acid environment where lysozyme exists (pH5.0, a simulated intracellular environment) and the least in the PBS (pH7.4, a simulated physiological environment).2. The interaction between ND-PEG-GLY-MTX and cells was carried out by MTT assay, flow cytometry analysis and confocal laser scanning microscope. Using fluorescence microscopy and MTT assay, it was found that ND-PEG-GLY had almost no cytotoxicity. Flow cytometry analysis showed that ND-PEG-GLY-MTX had a selective interaction in the S phase of cell division, induced tumor cell apoptosis, and the curative effect was stronger than that of the free MTX. Confocal laser scanning microscope revealed that the amount of nanomedicine entering the cells was increasing with time, and was located in cytoplasm. The uptake of ND-PEG-GLY-MTX by HeLa cells was detected by flow cytometry, and it was found that the uptake of ND-PEG-GLY-MTX was time and temperature-dependent and the caveolin-mediated endocytic pathway.3. In vivo antitumor effects on both ND-DOX and ND-PEG-FA-DOX were studied using the tumor-bearing mice as the models. The average weight of mice with time showed that the nanomedicine had lower toxic side effects than DOX. The tumor volume change rate showed that the tumor growth of the nanomedicine treated group was slower than the PBS control group, and ND-PEG-FA-DOX treated group was more significant, which confirmed that it had a targeting tumor ability. Moreover, the mice were sacrificed for blood and organs collection. By the organ index diagram, the blood test and biochemical index, the result proved that the toxicity and side effects of the above nanomedicine system (ND-PEG-FA-DOX) for the mice livers was lower than that of the chemotherapy drug DOX.