The safety of engineered nano-objects is a burning societal concern, given the growing development of nanomaterials in a variety of products and of their exploitation for many different uses. Nanosafety regulations are still failing to appropriately address the issue of safe production and safe use of nano-based materials and products, while both the society and the nanotech industry are pushing for having well-defined safety indications. Two major areas are concerned with nanosafety assessment, i.e. environmental nanosafety, and human health safety. In the case of human beings, but also for many environmental living organisms, the interaction between NP and the body occurs at the level of the external body barriers (skin, respiratory and digestive mucosae), which are the first line of defence against external threats to the body integrity. The immune system (very complex in human beings, but sharing several phylogenically conserved mechanisms with invertebrates and even plants) is the defensive system that patrols the mechanical barriers and all the tissues in the body and that recognized and reacts to putative dangers. While the large majority of dangerous agents is represented by microorganisms, the immune system is also endowed with the capacity of recognizing and eliminating non-living particles. Based on size, shape, and surface characteristics, micro- and nano-particulate matter can be detected by innate/inflammatory cells and trigger reactions similar to those initiated by interaction with infectious microorganisms (extracellular bacteria, intracellular viruses). The extent and the duration of the innate/inflammatory reaction dictates the biological outcome, either a physiological defensive reaction that resolves and returns to baseline after elimination of the dangerous agent, or a persisting inflammation that can degenerate into a chronic pathological condition. To assess whether NP may or not pose a risk for human health, reliable approaches should be used. A variety of in vivo and in vitro assays have been proposed, several of which have been adopted by regulatory bodies. The problem of devising assays that are representative of the human NP effects in vivo and that can be predictive of putative risk must be seriously addressed, since several of the current assays are non-specific, partially representative and eventually unreliable. Issues that should be considered when devising ways for testing nanosafety are therefore the following: 1.toxicity of NP in real-life exposure scenarios; 2.effects on population groups with frail or anomalous immunity (babies, elderly, patients with chronic diseases); 3.NP changes due to interaction with surrounding agents (e.g., water, mucus, blood); 4.co-challenge with other agents (e.g. bacteria, pollen, allergens). How these situations could be reproduced in simplified assays predictive of risk will be discussed.
The problem of nanosafety: how to assess the fate of nano-bio interaction and predict risk.
D Boraschi
2014
Abstract
The safety of engineered nano-objects is a burning societal concern, given the growing development of nanomaterials in a variety of products and of their exploitation for many different uses. Nanosafety regulations are still failing to appropriately address the issue of safe production and safe use of nano-based materials and products, while both the society and the nanotech industry are pushing for having well-defined safety indications. Two major areas are concerned with nanosafety assessment, i.e. environmental nanosafety, and human health safety. In the case of human beings, but also for many environmental living organisms, the interaction between NP and the body occurs at the level of the external body barriers (skin, respiratory and digestive mucosae), which are the first line of defence against external threats to the body integrity. The immune system (very complex in human beings, but sharing several phylogenically conserved mechanisms with invertebrates and even plants) is the defensive system that patrols the mechanical barriers and all the tissues in the body and that recognized and reacts to putative dangers. While the large majority of dangerous agents is represented by microorganisms, the immune system is also endowed with the capacity of recognizing and eliminating non-living particles. Based on size, shape, and surface characteristics, micro- and nano-particulate matter can be detected by innate/inflammatory cells and trigger reactions similar to those initiated by interaction with infectious microorganisms (extracellular bacteria, intracellular viruses). The extent and the duration of the innate/inflammatory reaction dictates the biological outcome, either a physiological defensive reaction that resolves and returns to baseline after elimination of the dangerous agent, or a persisting inflammation that can degenerate into a chronic pathological condition. To assess whether NP may or not pose a risk for human health, reliable approaches should be used. A variety of in vivo and in vitro assays have been proposed, several of which have been adopted by regulatory bodies. The problem of devising assays that are representative of the human NP effects in vivo and that can be predictive of putative risk must be seriously addressed, since several of the current assays are non-specific, partially representative and eventually unreliable. Issues that should be considered when devising ways for testing nanosafety are therefore the following: 1.toxicity of NP in real-life exposure scenarios; 2.effects on population groups with frail or anomalous immunity (babies, elderly, patients with chronic diseases); 3.NP changes due to interaction with surrounding agents (e.g., water, mucus, blood); 4.co-challenge with other agents (e.g. bacteria, pollen, allergens). How these situations could be reproduced in simplified assays predictive of risk will be discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
