Lipoamino acids (LAA) are biocompatible and biodegradable biosurfactants, a promising alternative to viral vectors in gene delivery. LAA are constituted by a polar head, the amino acid, and a hydrocarbon (alkyl) chain usually from a fatty acid or fatty acid derivative, such as a fatty amine or a fatty alcohol. In this work, dodecyl LAA was produced from dodecylamine and natural l‐amino acids cystine (Cys), lysine (Lys), and phenylalanine (Phe) using an enzyme‐based approach with porcine pancreatic lipase. The self‐assembly behavior of LAA solutions, in the absence or presence of DNA, was studied by conductivity and fluorescence regarding the application as transfection agents. Conductivity measurements yielded important system parameters, including critical micelle concentration (CMC) and standard Gibbs energy of micellization (ΔG°_mic) for pure LAA systems, and apparent critical aggregation concentration (CAC_app) and apparent standard Gibbs energy of aggregation (ΔG°_agg) for the mixed LAA‐DNA systems. The CMC increased in the order of decreasing lipophilicity: (C₁₂Cys)₂ < C₁₂Phe < C₁₂Lys, CMC values were higher in the presence of DNA, suggesting the formation of a LAA‐DNA complex responsible for hindering the micellization process. Binding of the LAA with DNA was confirmed from fluorescence measurements for the ethidium bromide exclusion assay. Results suggest a weak interaction of the LAA with DNA which can be attributed to their relatively short dodecyl chains and/or the ionic strength of the buffer solution, supporting the role of hydrophobic interactions in complex formation between DNA and the oppositely charged surfactant in combination with electrostatic interactions. The CAC_app values decreased with increasing LAA hydrophobicity, reflecting the relevance of hydrophobic interactions in complex coacervation.

中文翻译：

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基于热力学和聚集特性的脂氨基酸DNA的自组装

脂氨基酸（LAA）是生物相容性和可生物降解的生物表面活性剂，是基因传递中病毒载体的有前途的替代方法。LAA由极性头，氨基酸和通常由脂肪酸或脂肪酸衍生物（例如脂肪胺或脂肪醇）衍生的烃（烷基）链组成。在这项工作中，十二烷基左心耳从十二和自然生产的升氨基酸胱氨酸（Cys），赖氨酸（Lys）和苯丙氨酸（Phe）使用基于酶的方法与猪胰脂肪酶结合使用。在不存在DNA的情况下，通过电导率和荧光将LAA溶液的自组装行为作为转染剂的应用进行了研究。电导率测量得出重要的系统参数，包括纯LAA系统的临界胶束浓度（CMC）和胶束化的标准Gibbs胶束能量（ΔG ° _mic），以及表观临界聚集浓度（CAC _app）和表观标准Gibbs聚集能（ΔG ° _agg）用于混合LAA‐DNA系统。CMC按亲脂性降低的顺序增加：（C ₁₂Cys）₂ <C ₁₂ Phe <C ₁₂ Lys，在存在DNA的情况下CMC值较高，表明形成了会阻碍胶束化过程的LAA-DNA复合物。LAA与DNA的结合由溴化乙锭排阻测定法的荧光测量结果证实。结果表明，LAA与DNA的相互作用较弱，这可归因于它们相对较短的十二烷基链和/或缓冲溶液的离子强度，从而支持了疏水相互作用在DNA与带相反电荷的表面活性剂结合形成复合物时的作用。静电相互作用。CAC_应用 值随LAA疏水性的增加而降低，反映了复杂凝聚中疏水性相互作用的相关性。