organisms. It will be essential to introduce the structural and reactivity data derived
from material science and toxicology studies to the safer design of CNPs in the
future. Knowledge about the fundamental characteristics of CNPs and ceria-based
material, new characterization techniques, and powerful theoretical methods need to
be developed to help us predict the biocompatibility of CNPs regarding safe and
effective applications in nanotechnology. Moreover, research should be directed
toward finding ways to decrease CNPs toxicity (such as antioxidants provided by
dietary source and supplements, metal chelators, passivators).
7 Conclusion
In the present study, the important transformations of CNPs that need to be considered when addressing their environmental and ecological effects are discussed and
summarized. The surface properties are crucial in understanding the environmental
behavior of CNPs in relation to their stability against agglomeration, mobility,
reactivity, and toxicity. The phase transformations of CNPs metallic core with (in)
organic compounds in different environmental scenarios significantly influence their
fate, transport, interactions with organisms, and consequence of bioaccumulation
and toxicity. The roles of surface properties and environmental transformations of
CNPs in the likelihood of toxicity mechanisms are further explored based on the
physical damage and chemical inhibition. Finally, important questions and research
directions in terms of identifying the toxicological risk factors and safer applications
of CNPs are highlighted. Overall, the findings characterizing and predicting the
environmental transformations and risks from manufactured CNPs should increase
our awareness of CNPs pollution. With increased knowledge and ongoing study, we
are urged to find strategies for mitigating the toxicities associated with CNPs
exposure. More important, we should foresee a future with better-informed and,
hopefully, more cautions manipulation for safe design and application of CNPs.
8 Summary
Increasing production and utilization of cerium oxide nanoparticles (CNPs) in recent
years have raised wide concerns about their biotoxicity. Numerous studies have been
conducted to reveal the toxicity of CNPs, but the results are sometimes contradictory. In this review, the most important factors in mediating CNPs toxicity are
discussed, including:
1. the roles of physicochemical properties (size, morphology, aggregation condition, surface charge, coating, and surface valence state) on CNPs toxicity;
2. the phase transfer and transformation process of CNPs in various aqueous,
terrestrial, and airborne environments;
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G. You et al.
from material science and toxicology studies to the safer design of CNPs in the
future. Knowledge about the fundamental characteristics of CNPs and ceria-based
material, new characterization techniques, and powerful theoretical methods need to
be developed to help us predict the biocompatibility of CNPs regarding safe and
effective applications in nanotechnology. Moreover, research should be directed
toward finding ways to decrease CNPs toxicity (such as antioxidants provided by
dietary source and supplements, metal chelators, passivators).
7 Conclusion
In the present study, the important transformations of CNPs that need to be considered when addressing their environmental and ecological effects are discussed and
summarized. The surface properties are crucial in understanding the environmental
behavior of CNPs in relation to their stability against agglomeration, mobility,
reactivity, and toxicity. The phase transformations of CNPs metallic core with (in)
organic compounds in different environmental scenarios significantly influence their
fate, transport, interactions with organisms, and consequence of bioaccumulation
and toxicity. The roles of surface properties and environmental transformations of
CNPs in the likelihood of toxicity mechanisms are further explored based on the
physical damage and chemical inhibition. Finally, important questions and research
directions in terms of identifying the toxicological risk factors and safer applications
of CNPs are highlighted. Overall, the findings characterizing and predicting the
environmental transformations and risks from manufactured CNPs should increase
our awareness of CNPs pollution. With increased knowledge and ongoing study, we
are urged to find strategies for mitigating the toxicities associated with CNPs
exposure. More important, we should foresee a future with better-informed and,
hopefully, more cautions manipulation for safe design and application of CNPs.
8 Summary
Increasing production and utilization of cerium oxide nanoparticles (CNPs) in recent
years have raised wide concerns about their biotoxicity. Numerous studies have been
conducted to reveal the toxicity of CNPs, but the results are sometimes contradictory. In this review, the most important factors in mediating CNPs toxicity are
discussed, including:
1. the roles of physicochemical properties (size, morphology, aggregation condition, surface charge, coating, and surface valence state) on CNPs toxicity;
2. the phase transfer and transformation process of CNPs in various aqueous,
terrestrial, and airborne environments;
196
G. You et al.