Toxicity of Metal-Organic Framework Nanoparticles: From Essential Analyses to Potential Applications

Owing to their immense design versatility, the number of novel metal-organic framework (MOF) structures and their proposed applications, especially for MOF nanoparticles, is exponentially increasing (Figure 1). But although the potential hazards of such nanosized particles have become evident, a systemic hazard assessment of MOF nanoparticles, including the evaluation of their toxicity as well as the potential risk of exposure, is often neglected. To date, their toxicity is typically only assessed when a medical application is intended, and the different potential routes of exposure are frequently incomplete or entirely overlooked.

Figure 1. Overview of different applications of MOF nanoparticles for which the aspect of induced nanotoxicity is relevant.

To draw the attention of researchers to this issue and to learn from it for a safer and more sustainable future, we therefore summarized the most important aspects of nanotoxicity, the current ‘state-of-the-art’ of the toxicity assessment of MOF nanoparticles, i.e. in vitro and in vivo studies, and the identified key aspects affecting their resulting toxicity in our tutorial review.

Chemical Society Reviews 2022, 51, 464-484. (DOI: 10.1039/D1CS00918D)

Moreover, we formulated recommendations for the ideal workflow of a hazard assessment of MOF nanoparticles (Figure 2), consisting of scientific research, risk assessment as well as risk management, in the context of their applications to foster their future synthesis in a way that they are ‘safe-and-sustainable-by-design’. Therefore, our tutorial review sheds light on the key aspects of nanotoxicity and emphasises the importance of its systematic assessment for MOF nanoparticles to pave the way towards their unlimited access to all fields of applications in a safe and sustainable manner.

Figure 2. Iterative process towards MOF nanoparticles that are safe-and-sustainable-by-design: design, synthesis, characterisation, and hazard assessment.