Linear poly ethylenimine

E. S. Tillman and N. S. Lewis, Mechanism of enhanced sensitivity of linear poly(ethylenimine) - carbon black composite detectors to carboxylic acid vapors , Sensors And Actuators B - Chemical 96, 329 (2003). 

Jeong, J.H., Song, S.H., Lim, D.W., Lee, H., and Park, T.G. (2001) DNA transfection using linear poly(ethylenimine) prepared by controlled acid hydrolysis of poly(2-ethyl-2-oxazoline). Journal of Controlled Release 73 391-399. 

A variety of mono-, di-, tetra-, and polydendron PAMAMs have been synthesized from simple amines as well as linear polyamine cores [2, 83, 124]. Linear poly(ethylenimines) with core multiplicities (Nc of ca. 300-400) have been shown to produce high-aspect ratio, rod-like dendrimers at generation 3 or 4 [2]. Their length is determined by the degree of polymerization (n) of the initiator core and their diameter is derived from the number of generations (see Scheme 3). 

The CROP of N-tetrahydropyranylazlridine results in the tetrahydropyran-protected linear poly(ethylenimine) and, thus, provides straightforward access to linear poly(ethylenimine) by acidic removal of the tetrahydropy-ran groups (Scheme 8.23) [136]. As discussed previously, linear poly(ethylenimine) cannot be prepared by simply polymerizing ethylenimine because of transfer reactions resulting in branched polymers. Poly(ethylenimine)s with polymerizable methacrylate side groups have been reported based on the CROP of 2-(l-aziridinyl)ethyl methacrylate (Scheme 8.23) [137]. Subsequent radical polymerization of the methacrylate moieties results in densely crosslinked... 

Linear-poly(ethylenimine) (L-PEI) has often been used for gene delivery as DNA/L-PEI complexes due to its high... 

Lee Y, Mo H, Koo H el al (2007) Visualization of the degradation of a disulfide polymer, linear poly(ethylenimine sulfide), for gene delivery. Bioconjug Chem 18 13-18... 

The absorption of water or moisture by solid polymers may be one of important phenomena in pure and applied polymer science. Therefore, the behaviors of water absorbed by a variety of polymers have been investigated by several physicochemical methods. In most cases, however, water is absorbed only in amorphous part, and thus the structure of water at the molecular level is not always definite. As for linear poly(ethylenimine) [poly(El)], we found two distinct crystalline hydrates, in which water exists stoi-chiometrically as "water of crystallization", and it was confirmed by the X-ray structure analyses that the formation of the hydrates is responsible for the remarkably hygroscopic nature of this crystalline polymer. 

Fig. 3 Synthetic schemes for (a) poly-L-lysine and (b) branched and linear poly(ethylenimine)...

H. Wang, X. Chen, and C. Pan, Linear poly(ethylenimine)-graft-poly(ethylene glycol) copolymers their micellization and secondary assembly, Journal of Colloid and Interface Science, vol. 320, no. 1, pp. 62—69, 2008. 

Meredith MT, Hickey DP, Redemann JP, Schmidtke DW, Glatzhofer DT (2013) Effects of ferrocene methylation on ferrocene-modified linear poly(ethylenimine) bioanodes. Electrochim Acta 92 226-235... 

YORK s, FRECH R, SNOW A and GLATZHOFER D, A comparative vibrational spec-troscopicstudy of lithium triflate and sodium triflate in linear poly(ethylenimine) , Electrochim Acta, 2001, 46,1533-1537... 

As Fig. 15b illustrates, the graphical relation appears to be linear for an interaction number of 3 to 4, if A 1. Alternatively, for A = 1, linearity is evident (Fig. 15c) when the interaction number is 5 to 6. Thus a large value of A is compatible with the smallest interaction number. Excimer formation occurs within the fluorescence lifetime, about 8 nsec. Within that time the pyrene-labeled amine side chains must approach within about 4 A of each other. For the 5.3% pyrenylpolyethylenimine derivative in ethanol, where no ground-state association occurs, the effective local concentration of pyrene on the polymer matrix is about 10-2 M, as calculated from excimer fluorescence. In aqueous solution, where clusters form within the polymer matrix, the effective local concentration of pyrene adduct must be even greater. The quantitative assessment of fluorescence intensities (Fig. 15) points to a minimum interaction number of 3 to 4 pyrenyl-labeled amine side chains, within the 8 nsec lifetime. Since A 1, it appears from (12) that kDM(A) kMD + kD. Thus excimer formation must be very rapid in the polymer environment. We can conclude, therefore, that the primary-amine side chains of poly-ethylenimine are very flexible and mobile. 

Poly (ethylenimine) (PEI) has been demonstrated as an efficient gene delivery vehicle both in vitro and in vivo (161-163). Linear (22 kDa) and branched PEI formulations of varying molecular weights (0.6-800 kDa) have been reported. While polyplexes from higher molecular weight branched PEIs (70-800 kDa) were found to be more efficient in vitro but on intravenous administration the smaller and linear PEIs seem in general to be more efficient (171). However, questions as to the... 

In the literature, linear polymers are referred to as poly(iminoethylene), and branched polymers as poly(ethylenimine), since the latter derive from the ring-opening polymerization of ethylenimine. In this review, both polymers will be referred to as PEI. Mention will be made, however, to their structure whenever opportune. 

Poly(ethylenimine) (PEI) has been examined extensively both in its classical, random branched topology [125] and in its linear form [126]. The various architectural and topological forms of PEI have been reviewed recently [127], Here we describe the first example of this polymer system as an ideal, hyper-branched molecular assembly. Synthesis of a tri-dendron poly(ethyleneimine) dendrimer derived from an ammonia core involved, first the selective alkylation of diethylenetriamine (DETA) with aziridine to produce a symmetrical core cell, namely tris-(-2-aminoethyl)amine. Subsequent exhaustive alkylations of the terminal amino moieties with activated aziridines [2, 127, 128], such as IV-tosyl- or N-mesylaziridine gave very good conversions to the first-generation protected... 

Linear polystyrene can be functionalized by various methods . The functional group capacity in these polymers diould not be too high otherwise, steric complications may arise. Poly(ethylene ycol) has been found to be most suitable for liquid-phase synthesis. This linear polyether and the block copolymers with functional groups at defined distances are chemically stable and soluble in a large number of solvents including water and can be precipitated selectively. Partially hydrolyzed poly(vinylpyrrolidone) and its copolymers with vinyl acetate were successfully applied in peptide synthesis. Poly(acrylic acid), poly(vinyl alcdiol), and poly-(ethylenimine) are less suitable for the sequential type synthesis because of the... 

Kobayashi S, Hiroishi K, Tokunoh M, Saegusa T. Chelating properties of linear and branched poly(ethylenimines). Macromolecules 1987 20 1496-1500. 

Fig. 11.6(b). The effect of pol5 er amphiphile branching on the aggregation of cetyl poly(ethylenimine) amphiphiles. Molecular weight of the poly(ethylenimine) polymer backbone prior to derivatisation was measured as 900 115 Da and 489 113 Da for the branched and the linear polymers respectively. 

Different micelle formulations based upon the amphiphilic polymer poly(ethylenimine), PEI, loaded with cyclosporine A and formed into tablets were tested for comparative drug absorption against CsA-in-water and CsA-microemulsion in a rat model by Le and colleagues [34]. Various PEI-CsA nanoparticles were examined, which differed based on linear or branched formations of the polymer. They determined that polymer hydrophobicity was the primary determinant to enhance CsA encapsulation and oral CsA absorption (bioavailabihty), and not polymer molecular weight or polymer branching. Polymers need at least 10% of their monomers to exhibit hydrophobicity in order to encapsulate sufficient drug and enable oral absorption enhancement. In this study, only the most hydrophobic PEI-CsA nanoparticles produced significantly enhanced CsA absorption compared to CsA-in-water, but none were superior to CsA-ME. 

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