Ethylacrylic acid

Similarly, a synthetic polyelectrolyte, poly(2-ethylacrylic acid) (PEAA) was shown to be active in artificial membranes and pH-sensitive.62 Modes of activity... 

External polymers can also be employed to control leakage of entrapped solutes. Adsorption of the hydrophobic polyelectrolyte poly(2-ethylacrylic acid) on phosphatidylcholine membranes causes the disruption of vesicle membranes (Figure 4.32) with small changes in pH (7.4—>6.5). The surface polyelectrolyte undergoes a well-defined conformational transition from an... 

Pentene. p-e-Amylene sym-methylethylethyl -ene. C,H mol wt 70.13. C 85.63%, H 14.37%. CH3CH2-CH=CHCHj. Prepn of mixture of cis and trims isomers by dehydration of 2-pentanol Norris, Org. Syn. coll, vol. I, (2nd ed., 1941) p 430. Prepn of the geometrical isomers from cis- and matts-a-methyl-d-ethylacrylic acids Lucas, Prater, J. Am. Chem. Soc. S9, 1682 (1937). Prepn of the cis form from 1-ethyl-2-iodobutyric acid with quinoline, of the trans form from I-ethyl-2-iodobutyric acid with sodium carbonate Sherrill, Matlak, ibid. 2134 prepn of both isomers from sec-amyl alcohol with HjSO( and diatomaceous earth at 90-110" for 3 hrs Lucas et al, ibid. 63, 22 (1941). Absorption spectra Carr, Stridden, ibid. 59, 2138 (1937). 

Interesting properties can be engineered into these materials by copolymerization. Copolymerization of 2-ethylacrylic acid or MAA with iV-[4-(phe-nylazo)phenyl]methacrylamide, a photosensitive monomer, results in polymers in which the interaction with lipid biolayers can be photoregulated [10, 11]. Thermally reversible polymers can be produced from poly(iV-isopropylacryla-mide), which is a water-soluble polymer at room temperature. The LCST (lower critical solution temperature) of the homopolymer is 32 °C at this temperature a reversible phase separation occurs. This LCST can be adjusted by copolymerization with more or less hydrophilic monomers. 

More recently, a family of acid responsive polymers based on a-alkyl acrylic acids such as methacrylic acid (MAA), ethylacrylic acid (EAA), propylacrylic acid, and butylacrylic acid (BAA) and their copolymers with alkyl acrylates or methacrylates have been explored for their ability to disrupt membranes and their potential as endosomal disruption polymers. The key feature of these poly(a-alkyl acrylic acids) is that they switch from a hydrophilic to a hydrophobic character as they become protonated (pH sensitive), and the switch to a hydrophobic character has been shown to disrupt membranes [68, 69]. The polymer, PPAA, has been shown to be 15 times more effective than PEAA at membrane disruption and to have maximum hemolytic activity at pH < 6, which is in the range of endosomal pH [68, 285]. PPAA has been successfully been used to enhance lipolyplex-mediated gene transfer [286] in vitro and wound healing by altering extracellular matrix organization and greater vascularization in vivo [286]. 

Schroeder UKO, Tirrell DA. Structural reorganization of phosphatidylcholine vesicle membranes by poly(2-ethylacrylic acid). Influence of the molecular weight of the polymer. Macromolecules 1989 22 765-769. 

These observations suggest that chain microstructure can influence in a significant way the interaction of synthetic polymers with lipid surfaces. An understanding of these results must await a more thorough study of the conformational properties of poly(o-ethylacrylic acid)s in aqueous solution. 

Ethylacrylic Acid (1-Methylenebutyric acid, l-butylene-2-carboxylic acid)... 

Metbyl-l-butylene-l-carboxylic Acid. See 2-Methyl-2-ethylacrylic Acid. 

See 1-Ethylcrotonic Acid. l-Methyi-2-ethylacrylic Acid iri-Amykt.- -carboxylic acid, 2-puUenf i-earboxylk nMd... 

Methyl-2-ethylacrylic Acid (2-Metihyl-l-pentenic acid, 2-methyl-l-butylene-l-carboxyUc acid, 2-ethylcrotmic acid)... 

Figure 2 illustrates that similar information can be obtained from the pH-dependent fluorescence of a polymer-bound pyrene probe. The conformational transition of a copolymer of 2-ethylacrylic acid and 1-pyreneacrylic acid appears in the fluorescence experiment as a large increment in If around pH 6.2. Covalent binding of the chromophore has little effect on the position or the shape of the transition. 

Figure 2. Fluorescence intentity (379 nm) onitted by 2-ethylacrylic acid/l-pyreneacrylic acid copolymer in phosphate buffers of differing pH. ( ) lipid-ftee polymer solutions (0) Polymer (0.9 mg/mL) plus DPPC (1.0 mg/mL).

The bulk polymerization of 2-ethylacrylic acid has been carried out by heating 1.00 gm of the monomer with 0.0328 gm of 2,2 -azobis(isobutyro-nitrile), after careful deoxygenation, in a sealed tube, for 12 hr at 65°C [32]. 

Poly(ethylacrylic acid) and poly(acrylic acid) and their interactions with vesicles over a range of pHs [140]. 

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