Analysis and correlations of metal-organic frameworks: applications and toxicity

Metal-organic frameworks (MOFs), organic and inorganic crystalline hybrids have been used for a variety of applications from catalysis, to gas storage and drug delivery. Studies have shown that generally, while such frameworks are more biocompatible than similar aspect ratio nanostructures, they are also more prone to transformation and disintegration due to their flexible and fragile nature as resulted from the structure assembly and implemented structure–function relationships. With extensive previous literature showing that materials with dimension nano such as carbon nanotubes, nanoparticles or quantum dots, have unique physicochemical properties that lead to increased biosystems’ reactivity, and with increasing concerns regarding adverse health effects upon such nanomaterials implementation, there is a growing interest to now evaluate the toxicological profiles of MOFs and how their characteristics can be controlled to lead to effective risk assessment and mitigation prior to their implementation. The interest is also motivated by the assumption that reactivity could be controlled with safe-by-design strategies. In this review, we are first describing general aspects related to MOFs and their synthesis, then we present the main trends of MOFs integration in synthetic applications, with subsequent focus on specifics of interfacing such structures with biosystems. Evidence assessment from both in vitro and in vivo studies is also being introduced to help reveal their toxicological profiles. Moreover, through a critical analysis of main advantages of these frameworks’ integration, we further raise awareness of their possible risk profiles and we suggest how they could be considered when envisioning further implementation of such nanomaterials. Lastly, we emphasize that alongside their benefits evaluations, data relevant to low dose and chronic exposure needs to emerge to thus be able to not only exploit MOFs dynamic nature but to ensure that such structure is not deleterious to environment and biological systems.