Biopolymer Surfactants for Sealing Electroporated Membranes

描述（由申请人提供）：质膜脂质双层结构的破坏及其随后的转运屏障功能丧失是创伤、肌营养不良、再灌注损伤和常见疾病中组织死亡的机制。质膜破裂后，代谢能量迅速耗尽，然后是急性细胞坏死。现在已经确定，某些生物相容性多嵌段共聚物表面活性剂，特别是泊洛沙姆188，在密封破裂的细胞膜方面是有效的，并且如果在损伤后几小时内递送，可以防止急性坏死。（附录A）。P188很可能很快成为创伤复苏液的标准成分，并将对医学治疗产生广泛影响。然而，P188可能不是膜修复的理想表面活性剂。它被氧自由基迅速降解成具有细胞毒性的片段。因此，有必要确定分子间的相互作用，负责表面活性剂密封破裂的膜，使更稳定的多嵌段共聚物表面活性剂，密封膜可以开发。我们将测试流行的假设，密封表面活性剂密封双层脂质膜这样做，通过改变界面水结构，从而降低膜张力，然后允许重组成脂质双层的膜脂质。我们将使用已建立的方法（附录C）来测量膜张力，同时扰动透化膜周围的水结构。将针对至少两种不同的细胞类型确定用于密封的阈值膜张力。我们计划确定密封功效作为共聚物表面活性剂结构的函数，并确定疏水和亲水部分的合适尺寸。我们还将在密封前后对膜结构和机械性能进行高分辨率测量（附录E）。最后，我们将进行平行研究，以确定表面活性剂拯救的细胞在增殖过程中是否表现出正常的表型，或表现出未修复的DMA引起的突变的影响。

DESCRIPTION (provided by applicant): Disruption of the plasma membrane's lipid bilayer structure with subsequent loss of its transport barrier function is the mechanism of tissue death in trauma, muscular dystrophies, reperfusion injuries and common diseases. Plasma membrane breakdown is followed by rapid metabolic energy exhaustion, then acute cellular necrosis. It is now well established that certain biocompatible multiblock copolymer surfactants, especially poloxamer 188, are effective in sealing of disrupted cell membranes and can prevent acute necrosis if delivered within a few hours after injury. (Appendix A). It is likely that P188 will soon be a standard component of trauma resuscitation fluids and will have a broad impact on medicine therapeutics. However, P188 may not be the ideal surfactant for membrane repair. It is rapidly degraded by oxygen free radicals into fragments that can be cytotoxic. Thus, it is necessary to determine the intermolecular interactions responsible for surfactant sealing of disrupted membranes so that more stable multiblock copolymer surfactants that seal membranes can be developed. We will test the prevailing hypothesis that sealing surfactants that seal bilayer lipid membranes do so by altering interfacial water structure, thus reducing membrane tension, which then permits reorganization of membrane lipids into a lipid bilayer. We will use established methods (Appendix C) to measure membrane tension while perturbing water structure around permeabilized membranes. The threshold membrane tensions for sealing will be determined for at least two different cell types. We plan to determine sealing efficacy as function of copolymer surfactant structure and determine suitable size of hydrophobic and hydrophilic moieties. We will also perform high resolution measurements of membranes structure and mechanical properties, before and after sealing (Appendix E). Finally, we will conduct studies in parallel to determine if surfactant rescued cells manifest normal phenotype during proliferation or exhibit effects of mutations caused by unrepaired DMA.