Molecular tools for imaging & photopharmacology
Molecular tools for imaging and photopharmacology
Light is a powerful, non-invasive tool that can be applied with precision in both space and time. As a result, it has been used in medical diagnostics and light-based therapies. Though light has a limited penetration depth in the body, it may prove useful for detecting or treating topical diseases, diseases in organs that can be reached with an endoscope, or during surgery. Despite advances in imaging techniques and light-responsive molecular tools, there is still a need for tools that are disease-specific and show limited unwanted interactions. Currently used fluorescent tracers for imaging of diseases often consist merely of an untargeted fluorescent dye or cannot be applied clinically.
In fluorescence optical imaging and light-based therapies (photopharmacology), selectivity issues can be tackled by using tracers or light-activated therapeutic agents that are specific to a given disease. Strategies that have been employed to achieve greater selectivity include using stimuli-responsive tools or coupling fluorescent dyes to a therapeutic agent. In the case of molecular imaging tools, this can lead to more accurate diagnoses as well as better visualization of diseases during surgeries. In photopharmacology, this can confine the toxicity of the light-activated therapeutic agent to diseased tissues while limiting damage to healthy cells.
Another aspect of photopharmacology aims to achieve greater selectivity for a disease by confining drug activity to an irradiated area and limiting side effects. This can be achieved by incorporating light-responsive elements into the drug's structure. These light-responsive elements can offer irreversible (photocages) or reversible control (photoswitches), both of which are suitable for different applications.