| Nanoparticles with the size of 100～200 nm are known to pass through fenestrate vessels by socalled the enhanced permeation and retention (EPR) effect, providing efficient accumulation in tumor detection. Studies showed that self-assembly nanoparticles with good EPR effect were prepared, including dextran with good water solubility and compatibility. But there was a little research about adding folic acid as targeting molecules to increase the accuracy of detection on this basis. We prepared folate-targeted fluorescence nanoparticles by self-assemble of deoxycholic acid conjugated dextran (Dex-DCA-FI/FA NPs) as cancer probes and researched these properties in this paper. Work in this thesis includes:1. Dex was modified by hydrophobic DC A. Dex-DCA NPs were prepared by self-assembly after investigation of the main influencing factors such as initial concentration and drop acceleration. The dimeter of obtained NPs (Dex-DCA0.24-1-1.25) was around 167.5 nm and the distribution was uniform, but stability of was not good and needed to be further optimized.2. Different amino substitution degree of Dex-DCA-NH2 NPs were prepared with addation of aminos to increase the stability of nanoparticles. Dex-DCA-NH2 NPs with a certain amount of positive charge were stable over 15 days in solution and 4 hours in cell medium.3. On the basis of Dex-DCA-NH2 NPs, Dex-DCA-FI/FA NPs were prepared by modification of fluorescein isothiocyanate (FITC) as fluorescence indicator and folic acid (FA) as targeted molecular. After assembly, three kinds of NPs Dex-DCA-FI 10o.5/FAo.5 NPS (Peak 134.9 nm), Dex-DCA-FI200.5/FA0.5 NPs (Peak 138.9 nm) and Dex-DCA-FI500.75/FA 0.25NPs (Peak 141.7 nm) with the size of 100～200 nm were created, which were stable over 14 days in solution and 4 hours in cell medium.4. Dex-DCA-FI200.5/FA 0.5 NPs had the ability of distinguishing between FR (+) cells and FR (-) cells. It was obviously that Dex-DCA-FI500.75/FA 0.25 NPs distinguished FR (+) cells between FR (-) cells. Dex-DCA-FI/FA NPs had good blood compatibility and low cytotoxicity on MCF-7 cells, Hela cells and A549 cells when the concentration was low, which hope to process in vivo animal experiment or be further modified by changed the labels or targeted moleculars. |
