Detergent dialysis

Rhoden, V., and Goldin, S. M. (1979). Formation of unilamellar lipid vesicles of controllable dimensions by detergent dialysis. Biochemistry, 18, 4173-4176. 

Kinetic measurements on II reconstituted in proteoliposomes are also consistent with the phosphorylation without transport. Il reconstituted by the detergent dialysis method into proteoliposomes assumes a random orientation the cytoplasmic domains face inward for 50% and outward for 50%. Those facing inward catalyze transport of external mannitol to the interior when E-I, HPr and P-enolpyr-uvate are included on the inside. Those facing outward convert external mannitol to external Mtl-P when HPr, E-I and P-enolpyruvate are included in the external medium. Comparison of the rates showed that the rate of external phosphorylation in this system was higher than the rate of transport. If transport and phosphorylation were obligatorily coupled, the rate of phosphorylation would not exceed the rate of transport [70]. 

Virosomes are virus-mimicking systems that contain liposomal bilayer and pH-dependent protein impregnated in the liposomal wall. Virosomes are produced by a detergent dialysis procedure. Many researchers have demonstrated that the virosomes facilitate the leakage of the encapsulated drugs from the endosomes into the cytoplasm. This is, however, complicated technology and, so far, no virosome products are used in the clinical practice. 

Since the protein-palmitate derivative can t be dissolved in organic solvent during homogenization of lipid to form liposomal membranes, it must be inserted into intact liposomes by detergent dialysis. 

Encapsulation of pDNA Using the Detergent Dialysis Procedure... 

The encapsulation of pDNA can also be accomplished with the use of a detergent dialysis procedure (12). In contrast to the PFV approach, the detergent dialysis procedure starts off with a micellar system and leads to encapsulation of pDNA in unilamellar liposomes called SPLP after detergent removal. Plasmid entrapment relies on a delicate balance between cationic lipid content and ionic strength of the solution. 

Figure 6 Encapsulation of plasmid DNA (pDNA) in small sterically stabilized liposomes [stabilized plasmid-lipid particles (SPLP)] using a detergent dialysis procedure. (A) Entrapped pDNA-to-lipid ratio as a function of the initial pDNA-to-lipid ratio (mg/mg). The initial lipid concentration was lOmg/mL. (B) Cryo-electron micrograph showing the structure of SPLP. The location of the plasmid is indicated by the striated pattern superimposed on the liposomes. The bar represents 100 nm.

In summary, the preformed vesicle approach and detergent dialysis procedure have enabled development of nucleic acid-based therapeutics with clinical utility. Further applications of these liposomal systems with new nucleic acid-based therapeutics such as small interfering RNA for gene silencing are being developed and have demonstrated promising results (28). 

Q Yang, X-Y Liu, M Hara, P Lundahl, J Miyake. Quantitative affinity chromatographic studies of mitochondrial cytochrome c binding to bacterial photosynthetic reaction center, reconstituted in liposome membranes and immobilized by detergent dialysis and avidin-biotin binding. Anal Chem 280 94-102, 2000. 

Liposomes carrying membrane proteins incorporated via different reconstitution methods (detergent dialysis, sonication etc.)... 

The methods described in the following section outline (1) the preparation of liposomes by filter extrusion and (2), detergent dialysis. In the past decades, a large number of methods of liposome preparation have been developed and refined. For comprehensive information, we refer to corresponding chapters of this book volume and the literature (36, 37). We favor the use of the two methods described in the following section that are recom-mendable because of their ease, versatility and high quality of liposomes they produce. 

Unilamellar liposomes are prepared by the detergent dialysis method (23). 

Such liposomes were prepared by detergent dialysis from a mixture of phosphatidyl choline and cholesterol. Antibody modified with Wglutaryl phosphatidyl ethanolamine (NGPA) (44) was incorporated into the liposomal membrane in the process of liposome preparation. PEG modified with NGPA was also... 

Membrane structures that contain the visual receptor protein rhodopsin were formed by detergent dialysis on platinum, silicon oxide, titanium oxide, and indium—tin oxide electrodes. Electrochemical impedance spectroscopy was used to evaluate the biomembrane structures and their electrical properties. A model equivalent circuit is proposed to describe the membrane-electrode interface. The data suggest that the surface structure is a relatively complete single-membrane bilayer with a coverage of 0.97 and with long-term stability/... 

Figure 7. Model of a single surface-bound membrane formed by detergent dialysis on an alkylsilanated electrode surface.

This simulation reproduces the essential features of the experimental data. A calculated capacitance for the tightly packed part of the surface-bound membrane (Cbl) can be obtained by treating Calk and Clip in series. The resistance can be similarly calculated from Ralk and Ru. The calculated values of 0.52 fiF/cm2 and 1325 ft cm2 are in good agreement with literature values for natural membranes (47-48). The best curve fit for the coverage factor, 0, was 0.97, which indicates formation of a relatively complete membrane by the detergent dialysis approach. 

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