Polyethylenimine branched

Kabanov et aLl2S studied the hydrolyses of p-nitrophenylesters in the presence of linear and branched benzylated polyethylenimine, 76 (BzPEI). The catalytic site... 

Oskuee RK, Philipp A, Dehshahri A, Wagner E, Ramezani M (2010) The impact of carboxyalkylation of branched polyethylenimine on effectiveness in small interfering RNA delivery. J Gene Med 12 729-738... 

Polyethylenimine (PEI) stock The transfection reagent (Aldrich, catalogue number 40,872-7 25 kDa branched PEI ). Stock solution of PEI is prepared as follows prepare stock solution of 100 mg/ml PEI in water, mix and further dilute to 1 mg/ml, neutralize with HCI and filter sterilize store 5 ml aliquots frozen. 

An interesting polymer constrained to a relatively compact conformation is polyethylenimine (PEI), which can be prepared by suitable polymerization of ethylenimine (Fig. 2) to give a highly branched rather than a linear macromolecule.19 The structure of a segment of this polymer is shown in Fig. 2. Approximately 25% of its nitrogens are primary amines, 50% secondary, and 25% tertiary.19 The branching of the polymer may be represented schematically as shown in Fig. 3. 

Fischer, D., Bieber, T., Li, Y., Elsasser, H-P, Kissel, T. (1999). A novel non-viral vector for DNA delivery based on low molecular weight, branched polyethylenimine effect of molecular weight on transfection efficiency and cytotoxicity. Pharm. Res., 16, 1273-12791. 

Tseng, W.C., Jong, C.M. (2003). Improved stability of polycationic vector by dextran-grafted branched polyethylenimine. Biomacromolecules, 4(5), 1277-1284. 

Wiseman, J.W., Goddard, C.A., McLelland, D., Colledge, W.H. (2003). A comparison of linear and branched polyethylenimine (PEI) with DCChol/DOPE liposomes for gene delivery to epithelial cells in vitro and in vivo. Gene Then, 10(19), 1654—1662. 

The last few decades has seen substantial progress in the fabrication of synthetic polymers with biocatalytic properties. A range of polymers has been examined as structural frameworks for the attachment of catalytic groups. For homogeneous catalysts, highly branched polyethylenimines have proved particularly versatile. Modified polystyrenes have served well as foundations for heterogeneous catalysts. 

Klotz and co-workers20) attached pendant butanoyl, hexanoyl, and dodecanoyl groups onto polyethylenimine (24), a highly branched water-soluble polymer containing approximately 25% primary and tertiary nitrogens and 50% secondary nitrogens. Roughly 8-10% of the residues of the polymer were acylated. The acyl-... 

PEI (polyethylenimine) Can be used in branched or linear form. Good potential for pulmonaiy therapy. Commonly used as copolymer component. Cationic density must be shielded (46-48)... 

Wightman, L., Kircheis, R., Rossler, V., Carotta, S., Ruzicka, R., Kursa, M., and Wagner, E. (2001) Different behavior of branched and linear polyethylenimine for gene delivery in vitro and in vivo. The Journal of Gene Medicine 3 362-372. 

Recently, new model polymers with a polyethylenimine backbone and nucleic acid base derivatives as pending side chains have been prepared55 the carboxy derivatives of adenine and thymine were grafted onto linear and branched polyethylenimine, and the carboxy derivatives reacted with the L-a-amino acid grafted polyethylenimine to form an amide bond by the p-nitrophenyl method. 

Interactions of the paft copolymers of adenine and thymine on linear and branched polyethylenimine with polynucleotides, poly A and poly U, were studied.57 From the Job plots58 of the A-PEI/T-PEI system at pH 7.4, formation of the complex was observed, the overall stoichiometry of the latter being 1 1 hypochromicity of the 1 1 complex was about 16%. The melting profiles are reversible upon heating and cooling. 

PEI-Mag2 precipitation/coating solution 2.5 g polyethylenimine 25 kD, branched (PEl-25gj. Sigma-Aldrich) plus... 

To obtain the SO-Mag2 nanomaterial by surface decoration of the SO-Magl nanomaterial via spontaneous adsorbtion of branched polyethylenimine 25 kD (PEI-25 /, mix 5 ml of aqueous SO-Magl suspension (20 mg Fe/ml) with 0.5 ml of aqueous PEI-25gj. solution (10 mg/ml), incubate for 1 h, and dialyze extensively against water. 

Branched polyethylenimine (BPEI) is a strong polybase even at high ionic strength [79, 80] and forms complexes with acids. Its behavior is determined by properties such as the branched structure, presence of three different types of amine groups, strong neighboring interactions between various amine groups, and the compact structure in aqueous solution. 

There are two different ways of preparing the simplest polyamine, polyethylen-imine. The first method leads to a commercial polymer. The parent monomer (aziri-dine) is used and the resulting polymer is highly branched due to pronounced chain transfer. The second method, leading to linear polyethylenimine, requires the preparation of polyoxazoline intermediate and is discussed in the next section. 

Polyethylenimine prepared in the usual way, i.e. with protonic acids in water solution at elevated temperatures is highly branched and has Mn < 100000. Under anhydrous conditions Mn < 3000. The kinetics of polymerization resembles a step-growth process. At 90% monomer conversion the main reaction product (80%) is the linear dimer [l-(2-aminoethyl) aziridine] 6I,62) ... 

A further class of synthetic gene vectors that has received attention in past years is cationic polymers, which condense and package DNA with high efficiency. Polymerized or oligomerized branched or nonbranched amino acid chains composed of lysine or arginine are common [59, 60]. Polyethylenimine, however, developed in 1995 by Boussif]61] and already used for... 

Polyethylenimine (PEI) is an integral polyelectrolyte that is available commercially, e.g., Polymin (BASF). It is formed by the ring-opening polymerization [reaction (28)] of ethyleneimine (aziridine). The resulting polyamine has about 50% of the expected secondary-amine functionality and about 50% primary and tertiary due to branching ... 

Polyethylenimine (PEI) is the most outstanding example for synthetic cationic polymers because of its wide range of applications. It can be synthesized in linear (LPEI) as well as in branched (BPEI) structures. LPEI possesses primary and secondary amino groups, whereas BPEI also features tertiary amino groups. BPEI usually has a ratio of primary to secondary to tertiary amino functionalities of 1 2 1 and up to 25% of these amino groups are protonated under physiological conditions. Such buffer capability can also be utilized for endosomal escape mechanisms. The amino... 

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