How safe are nanoscale metal-organic frameworks?

Revealing the synergistic impacts of ZIF-8 and copper co-exposure on zebrafish behavior, tissue damage, and intestine microbial community

The application of metal-organic frameworks (MOFs) has garnered significant attention in contemporary research. However, the impacts of MOFs on aquatic environments remain largely unclear. This study revealed that the water stability of Zeolitic Imidazolate Framework-8 (ZIF-8) is influenced by its concentration, with lower concentrations resulting in higher percentages of Zn2+ release. At 10 mg/L, ZIF-8 significantly reduced zebrafish locomotor activity, with total swimming distance decreasing by approximately 40.5%. Oxidative stress and neurotoxicity markers, reactive oxygen species (ROS), and acetylcholinesterase (AChE) levels increased by 2.18-2.24-fold and 1.92-2.24-fold, respectively. Zebrafish ingestion of ZIF-8 was observed, with further analysis showing severe vacuolization and necrosis in tissues, as well as a significant increase in the relative abundance of Proteobacteria in the gut microbiota. Additionally, the study examined the toxicity of co-exposure to ZIF-8 and other pollutants. When ZIF-8 and copper (Cu) were simultaneously introduced, zebrafish survival rates dropped significantly to 79.2%. Co-exposure caused more severe behavioral impairments, with swimming distance reduced by approximately 53.0%, compared to individual exposures to ZIF-8 or Cu. ROS and AChE levels rose by 2.68-3.37-fold and 2.93-3.77-fold, respectively, while tissue vacuolization and necrosis became more pronounced. The relative abundance of Proteobacteria increased to 92.2%. This study provides critical insights into the environmental and ecological impacts of MOFs, emphasizing the necessity of considering these effects for their sustainable application.

Metal-organic frameworks as thermocatalysts for hydrogen peroxide generation and environmental antibacterial applications

Reactive oxygen species (ROS) are highly reactive, making them useful for environmental and health applications. Traditionally, photocatalysts and piezocatalysts have been used to generate ROS, but their utilization is limited by various environmental and physical constraints. This study introduces metal-organic frameworks (MOFs) as modern thermocatalysts efficiently producing hydrogen peroxide (H2O2) from small temperature differences. Temperature fluctuations, abundant in daily life, offer tremendous potential for practical thermocatalytic applications. As proof of concept, MOF materials coated onto carbon fiber fabric (MOF@CFF) created a thermocatalytic antibacterial filter. The study compared three different MOFs (CuBDC, MOF-303, and ZIF-8) with bismuth telluride (Bi2Te3), a known thermocatalytic material. ZIF-8 demonstrated superior H2O2 generation under low-temperature differences, achieving 96% antibacterial activity through temperature variation cycles. This work advances potential in thermoelectric applications of MOFs, enabling real-time purification and disinfection through H2O2 generation. The findings open interdisciplinary avenues for leveraging thermoelectric effects in catalysis and various technologies.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Biomarkers of exposure and effect in human biomonitoring of metal-based nanomaterials: their use in primary prevention and health surveillance

Metal-based nanomaterials (MNMs) have gained particular interest in nanotechnology industry. They are used in various industrial processes, in biomedical applications or to improve functional properties of several consumer products. The widescale use of MNMs in the global consumer market has resulted in increases in the likelihood of exposure and risks to human beings. Human exposure to MNMs and assessment of their potential health effects through the concomitant application of biomarkers of exposure and effect of the most commonly used MNMs were reviewed in this paper. In particular, interactions of MNMs with biological systems and the nanobiomonitoring as a prevention tool to detect the early damage caused by MNMs as well as related topics like the influence of some physicochemical features of MNMs and availability of analytical approaches for MNMs testing in human samples were summarized in this review. The studies collected and discussed seek to increase the current knowledge on the internal dose exposure and health effects of MNMs, highlighting the advantages in using biomarkers in primary prevention and health surveillance.