The Research Of Dual-fluorescence Drug-loaded Liposomes Interact With Cell

Liposomes have widespread applications in drug delivery because of their various advantageous properties. Consequently, there has been increasing attention on the research of liposome-cell interaction and its performance as a drug carrier. The work of this thesis is investigation of interaction between cells and various types of drug-loaded liposomes. First, three types of dual-fluorescent liposomes, including anionic liposomes, cationic liposomes and PEG liposomes were prepared. All liposomes were labeled with FITC on the suface and fluorescent drugs were encapsulated within liposomes. Then, cells were incubated with liposomes at different time. Laser scanning confocal microscopy was used to study the interaction between the liposomes and cells. The work of this thesis is as follows:(1) Preparation and characterization of dual-fluorescent drug-loaded liposomesAnionic doxorubicin and protoporphyrin liposomes used in the thesis were prepared by film dispersion method using unlabeled dipalmitoyl phosphatidylethanolamine (DPPE), FITC labeled DPPE, cholesterol, and the fluorescent drug doxorubicin, protoporphyrin. Cationic liposomes and PEG liposomes were synthesized by adding Octadecylamine or polyethylene glycol - dipalmitoyl phosphatidylethanolamine (PEG-DPPE) based on anionic liposomes. Zeta-potentials, shape and size of the as prepared liposomes were characterized. Appropriate liposomes needed in the following experiments were obtained.(2) Investigation of dual-fluorescence doxorubicin liposome-cell interactionLaser confocal scanning image was characteristic of Hela cells incubated with FITC labeled DOX-liposomes. The different fluorescence distribution results of FITC and FITC labeled DOX-liposomes were investigated to study the mechanisms involved in liposome-cell interaction. First, the cell incubation condition wad optimized and it was found that the fluorescence distribution in Hela cells could be observed more clearly in the absence of serum. Among three types of dual-fluorescence doxorubicin liposome, PEG liposome was shown to have the highest efficiency in delivering doxorubicin to ite target site-nucleolus.(3) dual-fluorescence protoporphyrin liposome-cell interactionThe interaction between three types of dual-fluorescence protoporphyrin liposomes and Hela cells were studied under the same conditions as doxorubicin liposomes using the same methods. In this case, cationic and PEG liposomes were more efficiently in delivering protoporphyrin to its target area-cell membrane and cytoplasm than anionic liposomes. Compared with above doxorubicin liposomes, the corresponding types of protoporphyrin liposomes were less efficient in delivering drugs to its target sits.