A Model System for Cell-Specific Labelling Via Self-Destructing Devices

这一提议旨在为一系列分子装置的开发奠定基础，这些分子装置可以进入细胞，携带一种有用的小分子，以“关闭”的形式进入细胞，但在细胞内被触发“自毁”，释放处于活性状态的小分子，并锁定在细胞内。该装置将由三部分组成：一个可溶于水的小分子，因此不能穿过具有该装置所需功能的细胞膜；一个连接体，它包含关闭小分子活性的基团，也包含允许该装置穿过脂膜的脂链；一种激活剂部分，它与仅在所需的目标细胞中发现的触发物质反应，并使装置自毁，使处于活性状态的小分子从脂链中分离出来，并因此在细胞内部固定。由于这是一项主要验证研究，我们将使用脂质体(由包围在水的内部的脂双层组成的囊泡)作为细胞模型，在脂膜物种内固定化，例如可能在感兴趣的细胞中发现的酶，并证明该装置可以穿过脂膜，进入内部，与触发物质反应，从而释放活性形式，固定在脂质体中。脂质体的模型工作对于在具有可控变量的简单系统中证明装置的原理和发展化学至关重要，以便当它们应用于细胞工作时，它们的行为被充分理解和很好地描述。原理将在小分子是发光络合物的情况下得到证明，因为这是我们探索设备行为时进行表征研究的理想选择，但最终它可能是一种化疗药物，以完全相同的方式输送，以相同的方式靶向细胞。该设备的发光部分将是已知发光的过渡金属络合物(最初是Re，但也包括Ru和Ir)，随着化学的发展，触发器将被一系列化学物种激活，但我们还将包括糖和磷酸基团，以允许被糖苷酶和磷酸酶激活。

This proposal aims to lay the foundations towards the development of a series of molecular devices which can enter cells carrying a useful small molecule in a 'switched off' form, but within the cell are triggered to 'self destruct' freeing the small molecule in its active form and locked in the cell.The device will consist of three parts:A small molecule which is water-soluble and thus could not cross cell membranes (which are lipid-based) which has the desired function of the device;A linker which contains groups which turn off the small molecule's activity, and also contains lipid chains allowing the device to cross lipid membranes;An activator section which reacts with a trigger species found only in the desired, targeted cells, and causes the device to self-destruct, freeing the small molecule in its active state, separated from the lipid chains, and thus immobilised in the interior of the cell.As this is a proof-of-principal study we will use liposomes (vesicles consisting of a lipid bilayer surrounding an aqueous interior) as models for cells, immobilising within the lipid membrane species such as enzymes which may be found in the cells of interest, and demonstrating that the devices can cross the lipid membrane, enter the interior, react with the trigger species and thus liberate the active form, immobilised in the liposome. The model work with liposomes is vital to prove the principal and develop the chemistry of the devices in simple systems with controllable variables so that their behaviour is fully understood and well characterised when they are applied to cell work. The principal is to be demonstrated in the case in which the small molecule is a luminescent complex, as this is ideal for characterisation studies as we explore the behaviour of the devices, but eventually it could be a chemotherapy agent, delivered in exactly the same manner, with cells targeted in the same way. The luminescent sections of the device will be complexes of transition metals of known luminescence (initially Re, but also Ru and Ir), and the triggers will be designed to be activated by a series of chemical species as we develop the chemistry, but also we will include sugar and phosphate groups, to allow activation by glycosidase and phosphatase enzymes.