The usage of engineered nanomaterials (NM) offers many novel products and applications with advanced features, but at the same time raises concerns with regard to potential adverse biological effects. Upon release and emission, NM may interact with chemicals in the environment, potentially leading to a co-exposure of organisms and the occurrence of mixture effects. A prominent idea is that NM may act as carriers of chemicals, facilitating and enhancing the entry of substances into cells or organisms, subsequently leading to an increased toxicity. In the literature, the term 'Trojan-horse effect' describes this hypothesis. The relevance of this mechanism for organisms is, however, unclear as yet. Here, a review has been performed to provide a more systematic picture on existing evidence. It includes 151 experimental studies investigating the exposure of various NM and chemical mixtures in ecotoxicological in vitro and in vivo model systems. The papers retrieved comprised studies investigating (i) uptake, (ii) toxicity and (iii) investigations considering both, changes in substance uptake and toxicity upon joint exposure of a chemical with an NM. A closer inspection of the studies demonstrated that the existing evidence for interference of NM-chemical mixture exposure with uptake and toxicity points into different directions compared to the original Trojan-horse hypothesis. We could discriminate at least 7 different categories to capture the evidence ranging from no changes in uptake and toxicity to an increase in uptake and toxicity upon mixture exposure. Concluding recommendations for the consideration of relevant processes are given, including a proposal for a nomenclature to describe NM-chemical mixture interactions in consistent terms.
Environmental mixtures of nanomaterials and chemicals: The Trojan-horse phenomenon and its relevance for ecotoxicity.
Steffi Naasz,R. Altenburger,D. Kühnel
Published 2018 in Science of the Total Environment
ABSTRACT
PUBLICATION RECORD
- Publication year
2018
- Venue
Science of the Total Environment
- Publication date
2018-09-01
- Fields of study
Medicine, Chemistry, Environmental Science
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- ecotoxicological model systems
In vitro and in vivo experimental systems used to study environmental effects of nanomaterials and chemicals.
Aliases: ecotoxicological in vitro and in vivo model systems
- evidence categories
A classification scheme used to group reported nanomaterial-chemical mixture outcomes across uptake and toxicity responses.
Aliases: seven categories
- nanomaterial-chemical mixture exposure
Joint exposure to an engineered nanomaterial and a chemical in the environmental or ecotoxicological setting considered in the review.
Aliases: NM-chemical mixture exposure, mixture exposure
- nomenclature for nanomaterial-chemical mixture interactions
A proposed consistent set of terms for describing interactions between nanomaterials and chemicals in mixtures.
Aliases: consistent terms
- systematic review
A structured literature review that searches, selects, and synthesizes studies according to predefined criteria.
Aliases: review
- toxicity
Adverse biological effects measured after exposure to a nanomaterial, a chemical, or their mixture.
Aliases: toxic effects
- trojan-horse phenomenon
A hypothesis that engineered nanomaterials can carry associated chemicals into cells or organisms and increase internal exposure.
Aliases: Trojan horse effect, Trojan-horse effect
- uptake
The entry or internalization of a substance into cells or organisms as assessed under mixture exposure.
Aliases: substance uptake