Exploring Metal-Organic Frameworks as Multifunctional Materials for Biological and Environmental Applications

Metal-Organic Frameworks (MOFs) have attracted increasing attention over the past two decades due to their highly ordered crystalline nature, large specific surface area, possibility of structural modulation, and versatility in host–guest interactions. These unique characteristics make them promising materials not only for traditional applications such as gas storage and catalysis, but also in more advanced fields, including biomedicine and environmental purification. This doctoral thesis is dedicated to the study of MOFs as multifunctional platforms, with particular emphasis on their biomedical potential and complementary applications in the environmental field. The first part of this work focuses on zeolitic imidazolate framework-8 (ZIF-8), a prototypical MOF that combines structural stability, good biocompatibility and pH-dependent degradation. Thanks to these properties, ZIF-8 has been investigated as a nanocarrier for therapeutic molecules in two different biological contexts. On the one hand, its ability to encapsulate and release anticancer drugs has been explored, highlighting its potential in the development of new, more selective chemotherapy strategies with lower systemic toxicity. On the other hand, ZIF-8 has been evaluated for potential veterinary applications, particularly in the treatment of ruminal acidosis in ruminants, where its ability to load and release bioactive compounds in response to an acidic environment represents a promising approach to counteract this widespread metabolic dysfunction. The work also considered the porphyrin MOF PCN-224, characterized by a highly ordered structure, large mesoporous channels and excellent photophysical properties. In this case, the material was used as a platform for the delivery of paramagnetic ions, in particular gadolinium and manganese, in order to explore its use as a multifunctional agent for nuclear magnetic resonance imaging (MRI). The incorporation of these metals has made it possible to obtain systems with modifiable relaxivity profiles, with the aim of overcoming some of the limitations of conventional contrast agents, especially their potential toxicity. Finally, the environmental aspect of MOFs was addressed through the use of ZIF-8 as an adsorbent for the removal of pesticides from wastewater. Given the growing concern about the persistence of agrochemicals in aquatic ecosystems, the ability of ZIF-8 to adsorb Linuron, a herbicide that persists in the environment after use due to its chemical stability, was systematically evaluated. This study highlights how MOFs can contribute to sustainable water resource management, expanding their role beyond the biomedical field and emphasizing their versatility as materials at the interface between health and ecology. Overall, this doctoral research offers a comprehensive and integrated overview of the use of MOFs already known for specific applications in various fields. The study demonstrates how materials such as ZIF-8 and PCN-224 can be effectively adapted to biomedical, diagnostic and environmental contexts. The results collected contribute to reinforcing the vision of MOFs as versatile and multifunctional platforms capable of providing concrete solutions to current problems in medicine, diagnostics and environmental sustainability.