Study of bio-based nanomaterials inflammation potential in a zebrafish embryo model.

The increasing development of new biomaterials requires animal models experimentation to demonstrate their biocompatibility and their interactions in biological milieu. To reduce or avoid the extensive use of higher vertebrates, the zebrafish embryos can be used as a well-suited model for testing materials at nanoscale. Zebrafish embryos are considered a promising bridge model between in vitro and in vivo research, achieving the requirements of reduction and replacement in conducting experiments using full- grown animals. The nanomaterials developed need to be examined to evaluate their safety on humans, which implies the absence of adverse effects such as chronic inflammation, toxicity and necrosis. To test biological interactions and bioactive effects of nanomaterials we used different methods: the classic Fish embryo toxicity acute (FET) test characterized by the presence of chorion, the natural barrier that envelopes and protect a fish embryo, and a modified FET test, in which the embryos are treated without the chorion. By the use of classic and modified FET, we compared the effects of novel bio-based nanoparticles developed within the BIOMAT EU-H2020 funded project (GA nr. 953270), taking into consideration the inflammation as main adverse effect. The inflammatory process is investigated by qPCR, analyzing the level of genes as il8, il6, il1β, tnfα, nfkbia, nfk2, known to have an important role within this pathway, and by the evaluation of neutrophils recruitment, taking advantage of the Sudan Black staining. The high level of genetic homology to humans (70%), besides the simplicity of structures in development, makes the zebrafish embryos model a powerful system to predict and translate the effects observed on human beings, besides the toxicity assessment of nanomaterials on the environment.