Copolymerization of Chitosan Selectively Grafted by Polyethylene glycol as DNA Delivery Vectors

Cationic liposomes composed of 3-[N-(N’,N’-dimethylaminoethane)-carbamoyl] cholesterol (DC-chol) and dioleoylphosphatidylethanolamine (DOPE) have previously been shown to have applications in gene delivery. Our study aims to explore the effects of inclusion of polyethylene glycol (PEG) and using different molar ratios of DC-chol/DOPE on size, zeta potential, cytotoxicity and DNA delivery of DC-chol/DOPE liposomes. Our results show that PEGylation reduces the cytotoxicity of DC-chol/DOPE liposomes, and, furthermore, PEGylated liposome-DNA lipoplexes are smaller in size and more uniform in size distribution than those that are not PEGylated. Additionally, toxicity against ovarian cancer SKOV-3 cells decreases with the amount of cationic DC-chol present in the formulation; however, decreased delivery of DNA to cellular nuclei is also observed. Transfection with the PEGylated liposomes was successfully demonstrated using plasmid DNA with a known functional outcome. These results offer further insight into physicochemical properties important for cationic liposomes as vehicles for DNA delivery and demonstrate the potential of PEGylated DC-chol/DOPE liposomes as systemic delivery carriers for DNA-mediated ovarian cancer therapy.

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Polyethylene Glycol-Conjugated Copolymers for Plasmid DNA Delivery

Pharmaceutical Research ◽

10.1007/s11095-004-9003-5 ◽

2005 ◽

Vol 22 (1) ◽

pp. 1-10 ◽

Cited By ~ 176

Author(s):

Minhyung Lee ◽

Sung Wan Kim

Keyword(s):

Polyethylene Glycol ◽

Plasmid Dna ◽

Dna Delivery ◽

Conjugated Copolymers

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Immunocytochemical detection of hepatic carbohydrate metabolic enzymes: Improved resolution with polyethylene glycol embedding and visio-bond semithin sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124367 ◽

1992 ◽

Vol 50 (1) ◽

pp. 792-793

Author(s):

Kuixiong Gao ◽

Randal E. Morris ◽

Bruce F. Giffin ◽

Robert R. Cardell

Keyword(s):

Polyethylene Glycol ◽

Glycogen Phosphorylase ◽

Phosphoenolpyruvate Carboxykinase ◽

Glycogen Synthase ◽

Metabolic Enzymes ◽

Silver Stain ◽

Accurate Localization ◽

Immunocytochemical Detection ◽

Semithin Sections ◽

Parenchymal Cells

Several enzymes are involved in the regulation of anabolic and catabolic pathways of carbohydrate metabolism in liver parenchymal cells. The lobular distribution of glycogen synthase (GS), phosphoenolpyruvate carboxykinase (PEPCK) and glycogen phosphorylase (GP) was studied by immunocytochemistry using cryosections of normal fed and fasted rat liver. Since sections of tissue embedded in polyethylene glycol (PEG) show good morphological preservation and increased detectability for immunocytochemical localization of antigenic sites, and semithin sections of Visio-Bond (VB) embedded tissue provide higher resolution of cellular structure, we applied these techniques and immunogold-silver stain (IGSS) for a more accurate localization of hepatic carbohydrate metabolic enzymes.

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Directional observation on lipid of male nectary of Lindera megaphylla hemsl. by the rapid embedding method with polyethylene glycol (PEG)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161151 ◽

1990 ◽

Vol 48 (3) ◽

pp. 718-719

Author(s):

Dai Dalin ◽

Guo Jianmin

Keyword(s):

Electron Microscope ◽

Polyethylene Glycol ◽

Chemical Reaction ◽

Traditional Method ◽

Osmium Tetroxide ◽

Unsaturated Lipid ◽

Embedding Method ◽

Long Period ◽

New Methods

Lipid cytochemistry has not yet advanced far at the EM level. A major problem has been the loss of lipid during dehydration and embedding. Although the adoption of glutaraldehyde and osmium tetroxide accelerate the chemical reaction of lipid and osmium tetroxide can react on the double bouds of unsaturated lipid to from the osmium black, osmium tetroxide can be reduced in saturated lipid and subsequently some of unsaturated lipid are lost during dehydration. In order to reduce the loss of lipid by traditional method, some researchers adopted a few new methods, such as the change of embedding procedure and the adoption of new embedding media, to solve the problem. In a sense, these new methods are effective. They, however, usually require a long period of preparation. In this paper, we do research on the fiora nectary strucure of lauraceae by the rapid-embedding method wwith PEG under electron microscope and attempt to find a better method to solve the problem mentioned above.

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