Wojciechowski Kamil, Orczyk Marta, Gutberlet Thomas, Trapp Marcus, Marcinkowski Kuba, Kobiela Tomasz, Geue Thomas
Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
Biochim Biophys Acta. 2014 Jul;1838(7):1931-40. doi: 10.1016/j.bbamem.2014.04.008. Epub 2014 Apr 16.
The interactions between a model phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and a biosurfactant Quillaja Bark Saponin (QBS) obtained from the bark of Quillaja saponaria Molina were studied using simple models of biological membranes. QBS is known to interact strongly with the latter, exerting a number of haemolytic, cytotoxic and anti-microbial actions. The interaction of QBS dissolved in the subphase with DPPC monolayers and silicon-supported bilayers was studied above the cmc (10(-3)M). Surface pressure relaxation and surface dilatational rheology combined with quartz crystal microbalance (QCM) and neutron reflectivity (NR) were employed for this purpose. The DPPC-penetrating abilities of QBS are compared with those of typical synthetic surfactants (SDS, CTAB and Triton X-100). We show that the penetration studies using high surface activity (bio)surfactants should be performed by a subphase exchange, not by spreading onto the surfactant solution. In contrast to the synthetic surfactants of similar surface activity, QBS does not collapse DPPC mono- and bilayers, but penetrates them, improving their surface dilatational elastic properties even in the highly compressed solid state. The dilatational viscoelasticity modulus increases from 204 mN/m for pure DPPC up to 310 mN/m for the QBS-penetrated layers, while it drops to near zero values in the case of the synthetic surfactants. The estimated maximum insertion pressure of QBS into DPPC monolayers exceeds the maximum surface pressure achievable in our setup, in agreement with the surface rheological response of the penetrated layers.
利用生物膜的简单模型，研究了模型磷脂1,2 - 二棕榈酰 - sn - 甘油 - 3 - 磷酸胆碱（DPPC）与从皂树（Quillaja saponaria Molina）树皮中提取的生物表面活性剂皂树树皮皂苷（QBS）之间的相互作用。已知QBS与后者强烈相互作用，具有多种溶血、细胞毒性和抗菌作用。研究了在临界胶束浓度（10⁻³M）以上，溶解在亚相中QBS与DPPC单层膜和硅支撑双层膜的相互作用。为此采用了表面压力松弛和表面膨胀流变学，并结合石英晶体微天平（QCM）和中子反射率（NR）。将QBS的DPPC穿透能力与典型的合成表面活性剂（SDS、CTAB和Triton X - 100）进行了比较。我们表明，使用高表面活性（生物）表面活性剂的渗透研究应通过亚相交换进行，而不是通过铺展在表面活性剂溶液上。与具有相似表面活性的合成表面活性剂不同，QBS不会使DPPC单层膜和双层膜塌陷，而是穿透它们，即使在高度压缩的固态下也能改善其表面膨胀弹性性能。膨胀粘弹性模量从纯DPPC的204 mN/m增加到QBS穿透层的310 mN/m，而在合成表面活性剂的情况下则降至接近零值。估计QBS插入DPPC单层膜的最大压力超过了我们实验装置中可达到的最大表面压力，这与穿透层的表面流变学响应一致。
