Nordic Life Science 1
CHEMISTRY // MOFS molecules under specific condit
ions such as pH. They can also serve as biocatalytic platforms, where their pores help stabilize and protect small enzymes potentially enhancing their activity,” explains Šimėnas. In biosensors, the structure of MOFs allows them to exhibit luminescence through various pathways like linker emission, ligand-to-metal charge transfer, and metal-toligand charge transfer. Their low toxicity and biodegradable nature are further advantages. Beyond MOFs in Vilnius Researchers at Vilnius University Faculty of Physics are focused on both the synthesis and the properties of MOFs – the ways in which they respond to their environment and how their structure, electrical, and magnetic characteristics change. “When we introduce gas molecules into the pores of these materials, we can observe how they attach to the metal centers and how this affects the magnetic properties. When the molecules are released, everything returns to its initial state. These reversible changes make it possible to design sensitive gas sensors,” explains Šimėnas. To understand what happens inside the material, scientists combine electron paramagnetic resonance (EPR) spectroscopy and dielectric spectroscopy. Although MOFs remain an important field, Šimėnas’ group is currently focused on next-generation hybrid structures and quantum technology applications, he says. “While we did a lot of MOF research five to ten years ago, we’re now more focused on hybrid perovskites – materials that, like MOFs, contain metal centers and organic molecules but have entirely different electronic properties,” he says. “Within life sciences, MOFs can be employed for targeted drug delivery, as their structures can be tuned to release therapeutic molecules under specific conditions such as pH. They can also serve as biocatalytic platforms, where their pores help stabilize and protect small enzymes potentially enhancing their activity.” Research in this field has been greatly strengthened by an ERC Starting Grant of EUR 2.5 million for Šimėnas’ project aimed at increasing the sensitivity of EPR spectroscopy. “Vilnius University now has one of the most advanced EPR laboratories, as well as strong partnerships stretching from Germany and the UK to the US and Japan. We strive to compete on a global scale – not just in terms of equipment but also in terms of ideas,” concludes Šimėnas. NLS In 1999, Yaghi constructed a very stable material, MOF-5, which has cubic spaces. Just a couple of grams can hold an area as big as a football pitch. NORDICLIFESCIENCE.ORG | 49 ILLUSTRATION ©JOHAN JARNESTAD/THE ROYAL SWEDISH ACADEMY OF SCIENCES