Membrane active peptides (MAPs) have potential applications in drug delivery systems and as antimicrobials. We previously showed that a cationic comb-type copolymer, poly(allylamine)-graft-dextran (PAA-g-Dex), forms a soluble inter-polyelectrolyte complex with an anionic MAP, the E5 peptide, resulting in significant enhancement of the membrane disruption activity of E5. In this study, we designed a novel comb-type cationic copolymer composed of a PAA main chain and thermoresponsive poly(N-isopropylacrylamide) graft chains (PAA-g-PNIPAAm). We hypothesized that the thermoresponsive hydrophilic/hydrophobic transition of the grafted polymer would regulate the membrane disruption activity of E5 peptide. Both the binding affinity of the complex and the membrane disruption activity of E5/PAA-g-PNIPAAm were found to be enhanced above the phase transition temperature of the grafted chain. Our analysis suggests that the hydrophilic/hydrophobic environment around the cationic polymer chain plays important roles in the enhancement of the activity of the anionic peptide.

中文翻译：

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热响应性阳离子梳型共聚物增强两亲性肽的膜破坏活性。

膜活性肽（MAPs）在药物递送系统中和作为抗菌剂具有潜在的应用。先前我们表明，阳离子梳型共聚物聚（烯丙胺）-接枝-右旋糖酐（PAA- g -Dex）与阴离子MAP E5肽形成可溶性的聚电解质间复合物，从而显着增强了膜E5的破坏活性。在这项研究中，我们设计了一种新型的梳型阳离子共聚物，该共聚物由PAA主链和热响应性聚（N-异丙基丙烯酰胺）接枝链（PAA- g-PNIPAAm）。我们假设接枝聚合物的热响应亲水/疏水转变将调节E5肽的膜破坏活性。发现复合物的结合亲和力和E5 / PAA- g- PNIPAAm的膜破坏活性都在接枝链的相变温度以上增强。我们的分析表明，阳离子聚合物链周围的亲水/疏水环境在增强阴离子肽的活性方面起着重要作用。