Study of the permeability of cellular membranes using proteoliposomes

渗透性是化合物通过生物屏障如皮肤、肺上皮或胃肠道的通道。除了这些外部屏障外，还存在内部屏障，限制化合物在身体的不同隔室（如血液，中枢神经系统和器官）之间的转移。这些屏障是生物体对化学威胁的天然防御，但同时它们不能完全不可渗透，因为营养，呼吸和排泄是基本的生理功能。渗透性在多个科学领域产生影响，如营养，药物吸收和分布以及毒理学。 在细胞水平，化合物的渗透性由两种机制调节。第一种机制是化合物通过细胞膜的被动扩散。该机制取决于化合物的物理化学性质。用简单的人工膜很容易研究被动扩散。第二种机制称为主动传输。膜转运蛋白可以从膜的一侧提取特定的化合物，并将其携带到另一侧。为了在实验室中研究这一过程，通常需要细胞模型或活细胞。事实上，主动运输需要部分细胞机器工作。简单的人工膜不能模拟主动转运。 我们建议使用新型人工囊泡，即脂蛋白体研究主动和被动扩散。蛋白脂质体是类似活细胞的人工和非细胞囊泡。特定的蛋白质可以包含在它们的膜中以实现主动运输。这些工具将有助于研究渗透性，包括使用非细胞模型的主动运输和被动扩散。 这项研究的挑战包括膜转运蛋白的提取和纯化，同时保持其活性，以及设计一个库功能的蛋白脂质体。这些挑战存在于自然科学和工程领域。经过五年的应用，在转运膜蛋白和蛋白脂质体方面取得的知识可以转化为其他项目，例如集成微流体设备的概念，甚至是多药耐药癌症的非细胞模型的设计。

Permeability is the passage of a chemical compound through a biological barrier such as the skin, the pulmonary epithelium or the gastrointestinal tract. In addition to these external barriers, internal barriers also exist limiting the transfer of compounds between the different compartments of the body like the blood, the central nervous system and the organs. These barriers are the natural defenses of the organism against chemical threats, but at the same time they cannot be completely impermeable as nutrition, breathing and excretion are essential physiological functions. Permeability has a impact in multiple fields of science like nutrition, drug absorption and distribution as well as toxicology. At the cellular level, permeability of a compound is regulated by two mechanisms. The first mechanism is passive diffusion of the compound through the cellular membrane. This mechanism depends on the physicochemical properties of the compound. It is easy to study passive diffusion using simple artificial membranes. The second mechanism is named active transport. Membrane transport proteins can extract specific compounds from one side of the membrane and carry them to the other side. To study this process in the laboratory, cellular models or living cells are typically required. Indeed, active transport requires part of the cellular machinery to work. Simple artificial membranes cannot model active transport. We propose to study active and passive diffusion using novel artificial vesicles, namely proteoliposomes. Proteoliposomes are artificial and non-cellular vesicles resembling living cells. Specific proteins can be included in their membrane to enable active transport. Such tools will facilitate the study of permeability including active transport and passive diffusion using non-cellular models. The challenges of this research includes the extraction and purification of membrane transport proteins while maintaining their activity as well as the design of a library functional proteoliposomes. These challenges lie in the field of natural science and engineering. After the five years covered by this application, the knowledge achieved on transport membrane proteins and proteoliposomes could be translated into additional projects such as the conception of integrated microfluidic devices or even the design of non-cellular models of multidrug resistant cancers.