22. March 2026
(CONNECT) Researchers at the Center for Life Sciences of the Paul Scherrer Institute (PSI) have observed at the molecular level how a light-switchable drug interacts with a biological receptor. This effect could lay the foundation for drugs that, when irradiated with light, are activated in one part of the body without impacting the rest with side effects, as detailed in a statement.
The team led by Jörg Standfuss observed the effects of the beta-blocker photoazolol-1. This drug acts on what are referred to as β-adrenergic receptors, which are located in the heart and in the smooth muscle tissue of the airways. Activated by adrenaline or noradrenaline, these receptors trigger stress responses. Photoazolol-1 inhibits these receptors, thereby lowering blood pressure.
Together with partners from the Consejo Superior de Investigaciones Científicas research institution in Barcelona, the team developed a molecule that contains an additional atomic group, an azobenzene group. “This atomic group flips when irradiated with violet light. Photoazolol-1 then has a bent section and becomes much bulkier overall”, explains Quentin Bertrand, a co-author of the current study.
This resulted in the creation of a curved form of photoazolol-1, which blocks fewer receptors. The researchers conclude from this reaction that the effect of the molecule can be regulated by light. Depending on the light exposure, heart cells could be made to move more slowly or faster in the laboratory. The investigations were carried out at the SwissFEL X-ray free-electron laser at PSI, which facilitated the visualization of ultrafast molecular processes. These observations of the effects of light could help with the design of new drugs.
The project is being supported through a research grant from the Swiss National Science Foundation (SNF). The study was published in the journal Angewandte Chemie. ce/ww
