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

该提案旨在为开发一系列分子装置奠定基础，这些装置可以以“关闭”的形式携带有用的小分子进入细胞，但在细胞内被触发“自我毁灭”，释放出活性形式的小分子并锁定在细胞中。该装置将由三部分组成：一种小分子，它是水溶性的，因此不能穿过具有该装置所需功能的细胞膜（以脂质为基础）；一种连接器，它包含关闭小分子活性的基团，还包含允许装置穿过脂质膜的脂质链；一种激活剂部分，它与只在期望的靶细胞中发现的触发物质发生反应，并导致装置自毁，释放出处于活性状态的小分子，与脂质链分离，从而固定在细胞内部。由于这是一项原理证明研究，我们将使用脂质体（由围绕水内层的脂质双层组成的囊泡）作为细胞模型，在脂膜物种（如可能在感兴趣的细胞中发现的酶）内固定，并证明该装置可以穿过脂膜，进入内部，与触发物种反应，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原理和开发设备的化学至关重要，这样当它们应用于细胞工作时，它们的行为就可以被充分理解和很好地表征。主要是在小分子是发光复合物的情况下进行演示，因为这是我们探索设备行为时表征研究的理想选择，但最终它可能是一种化疗药物，以完全相同的方式传递，以相同的方式靶向细胞。该装置的发光部分将是已知发光过渡金属的复合物（最初是Re，但也有Ru和Ir），触发器将被设计为由一系列化学物质激活，我们将开发化学，但我们也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.