Effect of Polycation Length on Its Complexation with DNA and with Poly(oxyethylene-block-sodium methacrylate)

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• 作者：Toni Andersson ; Susanna Holappa ; Vladimir Aseyev ; Heikki Tenhu
• 刊名：Biomacromolecules
• 出版年：2006
• 出版时间：November 2006
• 年：2006
• 卷：7
• 期：11
• 页码：3229 - 3238
• 全文大小：215K
• 年卷期：v.7,no.11(November 2006)
• ISSN：1526-4602

文摘

Polyelectrolyte complexes of a synthetic polycation with either a genomic DNA or a synthetic poly(oxyethylene-block-sodium methacrylate), POE-b-PMANa, have been studied in aqueous solutions as a function of cation:anion ratio, the degree of polymerization of the polycation, the ionic strength, and temperature using dynamiclight scattering and turbidity measurements. The polycation was a copolymer of methacryl oxyethyl trimethylammonium chloride and poly(oxyethylene) monomethyl ether monomethacrylate with 4-5 oxyethylene repeatingunits, PMOTAC-g-POE. The molar masses of the polycations in a homological series were 0.3, 0.9, and 2.1 ×10⁶ g/ mol. The amount of comonomers with poly(oxyethylene) tails in the copolymers was 15 mol %. Themolar mass of the POE-b-PMANa was 75000 g/mol and that of the POE-block was 5000 g/mol. The molar massof the polycation was shown to have a dramatic effect on the stability and size of the complexes formed by eitherof the polyanions. An increase in the polycation molar mass shifts the cloud point toward the lower polycationcontent in the complexes, and a macro phase separation occurs in the solutions with the cation to anion molarratios much below than 1:1. Increasing the ionic strength has a similar effect. Further addition of salt to turbidand phase-separated solutions results in dissociation of the complexes, and the polyions dissolve as individualmacromolecules. The effect of POE on the stability of polyelectrolyte complexes is discussed as well.