Particles and microbiota: interaction to death or resilience?

Applications of nanomaterials in health have been presented but humans are colonial organisms and a key component must be also considered, the microbiota. Nanoproducts are present in all industrial sectors, including food, cosmetics, hygiene, decoration, agriculture, environment, and construction. Their ubiquity in the biosphere is obvious and, as the first barrier with the environment, human microbiota are directly exposed to nanoobjects. Recent technological advances and new generation high-throughput analytical techniques allow to study the intimate interplay between nanoobjects and the different microbiota existing in skin, mouth, respiratory tract, gut, and vaginal environments. This chapter focuses on the various human microbiota and diverse strategies employed to characterize their interactions with nanoparticles, including potential experimental pitfalls. Specific adaptive responses of each microbiota and microenvironments to nanoobjects have been carefully analyzed herein. Understanding such adaptations is crucial for the development of safe nanotechnologies ranging from nanomedicine to nonbioindustrial fields.