Dissertation > Medicine, health > Pharmacy > Pharmacology

Study on the Interaction between Functionalized Nanodiamond Materials and Cells

Author ZhouXuePing
Tutor YangBinSheng;LiYingQi
School Shanxi University
Course Inorganic Chemistry
Keywords Nanodiamonds Doxorubicin Transferrin Tumor targeting therapy
Type Master's thesis
Year 2011
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In present cancer therapy, chemotherapy has been used widely and is one of most effective means. However, the vast majority of clinically used anticancer drugs are low molecular weight compounds that exhibit a short half-life in bloodstream and a high overall clearance rate. These small molecule drugs diffuse rapidly into healthy tissues and are distributed evenly within the body. As a consequence, relatively small amounts of the drug reach the target site and thus prevent effective treatment. One of the effective approaches is targeted delivery of drugs by incorporating them to appropriate carrier system. Nanocarrier has large specific surface area, high surface activity, high affinity to biomolecules and the superior advantages in its drug delivery. The size of biological macromolecules such as DNA, protein and virus is in the nanoscale. Therefore, nanotechnology can better examine the molecular and cellular changes caused by diseases in the tumor diagnosis. With the recent development in nanomedicine, many varieties of nanoparticles, such as dendrimers, micelles, nanocapsules, liposomes, fullerenes and nanotubes carbon etc., are applied as pharmaceutical delivery systems for drugs, DNA, and imaging agents. Among the various nanoparticles, nanodiamonds have recently received increasing attention for their noncytotoxic nature, together with unique strong and stable photoluminescense, tiny size and easy surface modification.1. This article first studied the adsorption of anticancer drug doxorubicin (DOX) by nanodiamonds. The adsorption curve was consistent with Langmuir isotherms absorption curves, with an adsorption saturation point of about 38.3±2.3μg/mg. From a fit of the experimental data to the Langmuir adsorption model, we obtained Ka=(1.13±0.06)×106 M-1. Second, the desorption of DOX from NDs has been studied. Result indicated that nanodiamonds carrying DOX (ND-DOX) have potential slow/sustained released capabilities. 2. HeLa cell was selected as the cell model, the interactions between FND-DOX and cells have been discussed via MTT assay, laser scanning confocal microscope and flow cytometry. The results showed that the FND-DOX nanoparticles can enter HeLa cells via a clathrin mediated endocytosis pathway and were mainly localized in the cell cytoplasm. Subsequently, drugs with maintained biocompatibility were detached from NDs slowly, and then migrate into the nucleus. In conclusion, we have demonstrated that fluorescence nanodiamonds (FNDs) not only can serve as effective drug carrier to carry drugs into cells, but also could be a useful fluorescence probes to investigate the interactions of drug-loaded nanoparticles and cells.3. According to ligand-receptor theory, a specific ligand (eg. folic acid, galactose residue, transferrin) coupled or adsorpted to a nanocarrier will interact with its receptor at target cell site, enhancing its active targeting. Here, transferrin was selected as the ligand and was convalently coupled to FNDs. The mechanism of FND-Tf entering HeLa cells was investigated using flow cytometry analysis. The results showed that the internalization of the FND-Tf goes through a temperature-, energy-, and clathrin-dependent pathway. The competitive inhibition assays indicated that transferrin-transferrin receptor interaction plays an important role in the cellular uptake of the FND-Tf. These findings implicates that FND-Tf has potential applications on biomedication.

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