Kazan Federal University, 420008, Kazan, Russia.
Magn Reson Chem. 2013 Nov;51(11):750-5. doi: 10.1002/mrc.4013. Epub 2013 Sep 20.
Polyanion-coated lipid vesicles are proposed to have an appreciable potential for drug delivery because of their ability to control the permeability of lipid bilayers by environmental parameters such as pH and temperature. However, details of the interaction of this class of polymers with lipids and their mechanisms of induced permeability are still being debated. In this work, we applied (1)H NOESY to study details of the interaction of polyacrylic acid (PAA) fractions of molecular weights 5 and 240 kDa with dimyristoylphosphatidylcholine vesicles. We showed that PAA of two different molecular masses modifies lipid bilayers increasing disorder and probability of close contact between polar and hydrophobic groups. PAA molecules adsorb near the interface of lipid bilayers but do not penetrate into the hydrophobic core of the bilayer and, thus, cannot participate in formation of transbilayer channels, proposed in earlier works. Increasing the molecular mass of PAA from 5 kDa to 240 kDa does not change the effect of PAA on the bilayer, although PAA240 forms a more compact structure (either intra-molecular or inter-molecular) and interacts more strongly with interface lipid protons.
聚阴离子脂质体由于其能够通过环境参数（如 pH 值和温度）控制脂质双层的通透性，因此在药物传递方面具有相当大的潜力。然而，这类聚合物与脂质的相互作用的细节及其诱导通透性的机制仍存在争议。在这项工作中，我们应用（1）H NOESY 研究了相对分子质量为 5 和 240 kDa 的两种聚丙烯酸（PAA）与二肉豆蔻酰磷脂酰胆碱囊泡的相互作用细节。结果表明，两种不同相对分子质量的 PAA 修饰脂质双层，增加无序性，并增加极性和疏水区之间的紧密接触的概率。PAA 分子吸附在脂质双层的界面附近，但不穿透双层的疏水区，因此不能参与跨双层通道的形成，这在早期的研究中被提出。相对分子质量从 5 kDa 增加到 240 kDa 不会改变 PAA 对双层的影响，尽管 PAA240 形成更紧凑的结构（无论是分子内的还是分子间的），并与界面脂质质子相互作用更强。
