Dextrans methylation

DDMC 2-Diethyl-aminoethyl-dextran-methyl methacrylate graft copolymer... 

Onishi Y, Eshita Y, Murashita A et al (2005) Synthesis and characterization of 2-diethyl-aminoethyl-dextran-methyl methacrylate graft copolymer for nonviral gene delivery vector. J Appl Polym Sci 98 9-14... 

STUDY OF DEXTRAN-METHYL METHACRYLATE GRAFT COPOLYMER... 

Onishi, Y. Maruno, S. Kamiya, S. Hokkoku, S. Hasegawa, M. (1978).Preparation and characteristics of dextran-methyl methacrylate graft eopoly-mer. Polymer,19, 325- 3>2%. 

Chapter 9 - 2-diethylaminoethyl(DEAE)-Dextran is still an important substance for transfection of nucleic acids into cultured mammalian cells by the reason of its safety owing to autoclave sterilization different from lipofection vectors. However, DEAE-Dextran may not be superior to lipofection vectors with cytotoxic and a transfection efficiency. A stable soap-less latex of 2-diethylaminoethyl(DEAE)-Dextran-methyl methacrylate( MMA) graft eopolymer (DDMC) of a high transfection activity has been developed as Non-viral gene delivery vectors possible to autoclave at 121 for 15 minutes.Transfection activity determined by the X-gal staining method show a higher value of 50 times or more for DDMC samples... 

Free flow. Dobry and Finn [Chem. Eng. Prog., 54, 59 (1958)] used upward flow, stabilized by adding methyl cellulose, polyvinyl alcohol, or dextran to the background solution. Upward flow was also used in the electrode compartments, with cooling efficiency sufficient to keep the main solution within 1°C of entering temperature. 

Nonionic hydrophilic Polyethylene glycol Soluble starch, methyl cellulose, pullulan Dextran Above samples plus hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide Distilled water 0.01 N NaOH DMSO Buffer or salt solution (e.g., 0.1— 0.5 M NaNO,)... 

The GBR resin works well for nonionic and certain ionic polymers such as various native and derivatized starches, including sodium carboxymethylcel-lulose, methylcellulose, dextrans, carrageenans, hydroxypropyl methylcellu-lose, cellulose sulfate, and pullulans. GBR columns can be used in virtually any solvent or mixture of solvents from hexane to 1 M NaOH as long as they are miscible. Using sulfonated PDVB gels, mixtures of methanol and 0.1 M Na acetate will run many polar ionic-type polymers such as poly-2-acrylamido-2-methyl-l-propanesulfonic acid, polystyrene sulfonic acids, and poly aniline/ polystyrene sulfonic acid. Sulfonated columns can also be used with water glacial acetic acid mixtures, typically 90/10 (v/v). Polyacrylic acids run well on sulfonated gels in 0.2 M NaAc, pH 7.75. 

Methyl cellulose Dextran Cellulose particles Starch... 

The presence of three hydroxyl groups per glucose unit was shown by the preparation of a triacetate and a tribenzoate. Six or seven methyla-tions (using dimethyl sulfate and concentrated alkali) of dextran did not raise the methoxyl content above 41% (theoretical maximum 45.6%). Also, Purdie methylations (using methyl iodide and silver oxide) and methylation with thallium ethoxide and methyl iodide were ineffective in raising the methoxyl content of methylated dextran above 43.5%. The maximum theoretical methoxyl content was eventually attained by modified Muskat methylations. 6 Partially methylated dextran suspended in anisole solution was treated with sodium in liquid ammonia, and the sodium salt of methylated dextran thus formed was allowed to react with methyl iodide. The methoxyl content of the partially methylated dextran was raised by three such methylations from 42% to 45.5% and by five such methylations from 30% to 45.4%. 

D-Glucose residue 1 would therefore appear as 2,3,4,6-tetramethyl-D-glucose on hydrolysis of methylated dextran D-glucose 2 as 2,3-dimethyl-D-glucose and the other three D-glucose residues as 2,3,4-tri-... 

Levi, Hawkins and Hibbert6 have recently confirmed the structure for L. mesenteroides dextran proposed by Fowler, Buckland, Brauns and Hibbert.34 Completely methylated dextran in an over-all yield of 71% was obtained by three methylations with dimethyl sulfate and sodium hydroxide, followed by six modified Muskat methylations. The methylated dextran was hydrolyzed at 140° with methanolic hydrogen chloride, and the mixture of methylated glucosides, obtained in 95% yield, was quantitatively separated by fractional distillation. 2,3-Di-methyl-D-glucose was identified by means of the phenylhydrazide of the corresponding D-gluconic acid. 

Peat, Schluchterer and Stacey6 later obtained a small amount (0.23%) of methyl 2,3,4,6-tetramethyl-n-glucoside from the hydrolytic products of a methylated L. dextranicum dextran, in addition to 90% methyl 2,3,4-trimethyl-D-glucosides, and on the basis of these results, postulated a minimum chain length of 550 units for this dextran. An appreciable amount of methyl dimethyl-D-glucosides was obtained, but these may not indicate side chain linkages since a mixture of dimethyl isomers was present, and the dextran was not fully methylated (only 44.5% methoxyl rather than 45.6%). 

Addition of an aqueous solution of PEG to a saturated aqueous solution of a-CD at room temperature did not lead to complex formation unless the average molecular weight of PEG exceeded 200 [46]. Moreover, carbohydrate polymers such as dextran and pullulan failed to precipitate complexes with PEG, and the same was true for amylose, glucose, methyl glucose, maltose, maltotriose, cyclodextrin derivatives, such as glucosyl-a-CD and maltosyl-a-CD, and water-soluble polymers of a-CD crosslinked by epichlorohydrin. These facts suggested to Harada et al. the direction for further research. 

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