Polybrene

Meisel etal. [18-20] were the first to investigate how the addition of a polyelectrolyte affects photoinduced ET reactions. They found that charge separation was enhanced as a result of the retardation of the back ET when poly(vinyl sulfate) was added to an aqueous reaction system consisting of tris(2,2 -bipyridine)ruthenium(II) chloride (cationic photoactive chromophore) and neutral electron acceptors [21]. More recently, Sassoon and Rabani [22] observed that the addition of polybrene (a polycation) had a significant effect on separating the photoinduced ET products in an aqueous solution containing cir-dicyano-bis(2,2 -bipyridine)ruthenium(II) (photoactive donor) and potassium hexacyano-ferrate(III) (acceptor). These findings are ascribable to the electrostatic potential of the added polyelectrolytes. 

Sassoon and Rabani [79] also prepared a two polymer system in which a chromophore was covalently bound to one polyelectrolyte and a donor or acceptor was electrostatically held by the other polyelectrolyte, and showed that its back ET underwent a similar retardation effect. They employed 26 as a photosensitizer, MV2+ as a mediator, and ferricyanide as an acceptor electrostatically bound to the added polycation (polybrene). 

EOF reversal Surfactants SDS, CTAB, Brij, Tween, quaternary amines, diaminopropane, diaminobutane, Polybrene ... 

Polybrene Low Permanent High Flexible Linear Backbone Moderate... 

LE-pectin/LTM-agarose//polybrene (or polyamine, quart.)/calcium chloride. 

Agarose/ Polystyrene- sulfonate Polybrene Polystyrene/Polybrene form the complex agarose is the thermally gelled precast polymer polybrene is the small polycation. 27... 

Capillary wall Generally, the most straightforward approach is to use an uncoated fused silica capillary. But sometimes this is not possible because of adsorption problems to the capillary wall, or other wall properties are needed to control the electroosmotic flow. In literature, there are multiple examples. Besides permanently coated capillaries, there are several descriptions of dynamic coatings available, e.g., triethanolamine, Triton X-100, Polybrene, and quaternary ammonium salts. The advantage of these dynamic coatings is that the coating can be renewed between injections, which could improve repeatability and reproducibility of the separation. 

Capillary coating can also stabilize the migration times and resolutions. This is in particular necessary in the case of peptide and protein analysis, because proteins tend to stick to capillary walls. Often low-concentration polyethylene oxide solutions are recommended as well as dynamic bilayer coating formed by a non-covalent adsorption of polybrene and polyvinylsulfonate (PVS). Due to the stability of the EOF, the variation of intra- and intercapillary migration time was less than 1% relative standard deviation (RSD) with basic analytes and peptides. 

Polymeric polyamines are also strongly adsorbed in the compact region of the electric double layer as a combination of multisite electrostatic and hydrophobic interactions. The adsorption results in masking the silanol groups and the other adsorption active sites on the capillary wall and in altering the EOF, which is lowered and in most cases reversed from cathodic to anodic. One of the most widely employed polyamine coating agents is polybrene (or hexadimetrine bromide), a linear hydrophobic polyquaternary amine polymer of the ionene type [129]. 

Dimethyl-l,5-diazaundecamethylene polymethobromide (Hexadimetbrene, polybrene) [28728-55-4], Purified by chromatography on Dowex 50 and/or by filtration through alumina before use [Frank Hoppe-Seyler s Z Physiol Chemie 360 997 1979],... 

Vandekerckhove, J., Bauw, G.. Puypi, M., Van Damme, J., and Van Montagu, M. 1985. Protein-blotting on Polybrene-coated glass-fiber sheets. Eur. J. Biochem. 152 9-19. 

Ru02 supported by polybrene increases the rate of reduction of [Ru(bipy)3]3+ by two orders of magnitude and the rate increases with increasing pH from 1 to 10 and increasing Ru02 concentration.293 Care should, however, be taken in interpreting these results since the rate of formation of [Ru(bipy)3]2+ rather than 02 was measured. Other workers have shown262 that 02 production in a similar system maximizes at pH 4 and does not occur above pH 7. 

Polybrene sold as hexadimethrine bromide (Sigma, St. Louis, MO). 

The next day, infect the HT-29 cells with luciferase or mock retroviral particles. A 2.5 ml solution containing retroviral particles is either prepared fresh or obtained from a frozen aliquot (see above). Prepare polybrene as 100 x stock solution (0.8 mg/ml) in 1 x PBS (can be stored at —20°C). Add polybrene to the tubes containing the retroviral particles at a final concentration of 8 pg/ml. Aspirate the medium from the HT-29 cells in the two T25 flasks. Initiate the infection by adding 2.5 ml of the solutions containing the luciferase or mock retroviral particles with polybrene to both flasks. 

Polybrene (hexadimethrine bromide) (Sigma, Cat 028K3730) make 8 mg/mL stock solution in H2O and keep at —20°C. 

First time transduction medium 50% retroviral supernatant, 27% (v/v) DMEM, 15% (v/v) heat inactivated FBS, 5% (v/v) WEHI-3B conditioned medium, penicillin-streptomycin, 1.0 xg/mL ciprofloxacin, 200 mM L-glutamine, 6 ng/mL recombinant murine IL-3 (Peprotech, Cat 213-13), lOng/mL recombinant murine IL-6 (Peprotech, Cat 216-16), 50-100 ng/mL recombinant murine stem cell factor (SCF Peprotech, Cat 250-03), 1% (v/v) HEPES, and 20 xg/mL polybrene. The total volume is 4 mL for each sample. 

Second time transduction medium 2 mL retroviral supernatant, 20 xg/mL polybrene, and 1% (v/v) HEPES. 

At the day of infection, remove the NIH3T3 cell medium and add virus supernatant serially diluted in 293T medium as 1 2, 1 8, and 1 16. Polybrene is added as 80 pg/mLinto retroviral supernatant. 

Eika C. On the mechanism of platelet aggregation induced by heparin, protamine and polybrene, Scand J Haematol 1972 9 248-257. 

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