Gemini surfactants: behaviour at interfaces and interaction with synthetic and biological macromolecules

人类基因组图谱计划已经允许鉴定与许多遗传疾病有关的基因和基因缺陷。基因治疗代表了在这些没有足够治疗方法的疾病中修复有缺陷的蛋白质表达。其基本思路是用“健康”基因取代“病态”基因，或添加新基因以促进治疗性蛋白质的合成。基因（质粒DNA）通过细胞膜转移到靶细胞，即转染，主要是利用病毒载体，用所需的DNA取代天然DNA。使用这类媒介的程序复杂、危险且昂贵。近年来，非病毒载体作为替代媒介进行了研究。我们发现表面活性剂（皂状）由两个带正电的头基和两个烷基尾部组成，由碳氢化合物间隔基团连接，可以作为有效的非病毒载体。在“辅助脂质”存在的情况下，它们与DNA形成的复合物已经被我们证明能够在某些细胞系中表达治疗性蛋白质。下一阶段的研究目标是提高这些非病毒载体的转染效率；(1)通过修饰表面活性剂的化学结构，使所得到的DNA复合物的形态更好地适应于通过细胞膜的转移；(2)提高我们对DNA进入细胞后从核内体释放的机制的认识。治疗药物局部给药系统的开发是全球公共和动物卫生机构的优先领域。然而，目前似乎很少有以加拿大为基础的研究关注这一活动。这里描述的项目将是保持加拿大在这一研究领域的前沿的重要一步。

The Human Genome Mapping Project has allowed the identification of genes and gene defects implicated in a number of inherited diseases. Gene therapy represents the repair of defective protein expression in these diseases where there are no adequate therapies available. The basic idea is to replace the "sick" gene with a "healthy" one or to add a new gene to promote the synthesis of a therapeutic protein. The transfer of the gene (plasmid DNA) across the cell membrane to the target, transfection, has been mainly pursued using viral vectors with native DNA having been replaced by the required DNA. The procedures using such vectors are complex, hazardous, and expensive. Recently, nonviral vectors have been studied as alternate agents. We have found that surface active agents (soap-like) consisting of two positively charged head groups and two alkyl tails, connected by a hydrocarbon spacer group, can act as effective nonviral vectors. The complexes they form with DNA, in the presence of a "helper-lipid," have been shown by us to be able to express a therapeutic protein within certain cell lines. The objective of the next stage of research is to improve the transfection efficiency of these nonviral vectors; (i) by modifying the chemical structure of the surfactant so that the morphology of the resulting complex with DNA is better adapted to transfer through the cell membrane and (ii) to improve our insight of the mechanism of release of the DNA from the endosome once it is within the cell. The development of topical delivery systems for therapeutic agents is a priority area, worldwide, for public and animal health agencies. However, at this time there appears to be little Canadian-based research focusing on this activity. The project described here will be an important step in keeping Canada at the forefront of this research area.