Adaptive Artificial Receptors for Biomimetic Functions

In recent years, chemists have developed efficient methods for making molecular containers from simple building blocks. These molecular containers are of great interest as chemists have shown that the hollow cavity within their centre can be used to capture a range of guest molecules on the inside the container. Chemists often choose to capture guest molecules with biological relevance as these systems then have the potential to then be used for medical applications; for example to treat diseases within our bodies.

These molecular containers are able to do this as they selectively capture the anticancer molecule within the central cavity of the molecular container, which protects them as they move around the body and, then, releases them at the site of the disease (i.e. a tumour).

However, one of the major drawbacks of many existing molecular containers is that because they are made from rigid artificial building blocks, these inflexible molecular containers are unable to display responsive behaviour. As a result, the rigid molecules containers, unlike biological systems, are not able to adapt to the changes in environment and, instead of being able to treat a disease at a specific site within our bodies, they will interact with different molecules within our bodies and lose their ability to effectively treat the disease at its source.

Therefore, in order to make full use of the potential of these molecular containers for medical applications within our bodies (e.g., anticancer treatments) we need to make sure that they can interact with only the desired guest molecule (e.g., a drug molecule) and not with all the other undesired molecules that exist within our bodies. Moreover, many existing molecular containers cannot be dissolved in water and, hence, are not compatible for use within our bodies.

The proposed research addresses these problems associated with existing rigid molecular containers and describes the development of a new type of molecular container that uses flexible building blocks made from biologically inspired components that are water compatible and, hence, can potentially be used in our bodies. These bioinspired molecular containers have specific sites incorporated into their central cavity which allows them to be able to selectively interact with the one desired guest molecule from a large mixture of guest molecules.

The ability of these flexible molecular containers to selectively interact with one molecule in a complex mixture of molecules is inspired by the "lock-and-key" mechanisms used by nature. Moreover, the flexible nature of the biologically inspired building blocks also allows these new molecular containers to undergo controlled changes in their shape so that they can completely break apart in order to release the guest molecule from the central cavity in a controlled manner when desired.

This responsive behaviour of the molecular container, for the controlled capture and release of one specific and desired guest molecule (for example, anti-cancer drug molecule) even in the presence of large numbers of other undesired guest molecules, means that they have the potential to adapt to the complicated environments found within our bodies. As a result of this responsive behaviour, these new flexible molecular containers have the potential to be used for biomedical applications e.g., capturing an anticancer drug molecule, transporting it to the site of tumour within our bodies and then releasing the anticancer drug at the tumour site in order to treat the disease in a more efficient manner than current anti-cancer treatments.

The development of these new molecular containers, which contain flexible biological building blocks, that are able to adapt to interact with one desired guest molecule from a complex mixture, have a clear advantage over many existing ones as they have the striking potential to carry out medical applications within our bodies, for example delivering a drug at a tumour.