Human Biomonitoring of Engineered Nanoparticles:An Appraisal of Critical Issues and Potential Biomarkers

The present paper deals with the applicability of biological monitoring to the assessment of exposure and possible effects deriving from exposure to engineered nanomaterials (NM). After establishing a conceptual framework in which human biomonitoring should be placed, the paper reviews the critical issues related to the unusual properties of NM affecting the implementation of biomonitoring activities for this new class of chemicals. Relying on the recent advances in the toxicogenomic, it is possible to assess whether specific biological pathways are activated or perturbed by specific NM. However, to evaluate if quantitative changes in these biomarkers can be used as indicators or predictors for toxicity in humans, validation on well characterised groups of exposed people is needed. At present, it appears more pragmatic to evolve NM-associated biomarker identification considering relevant biological responses found in environmental and occupational studies and assessing the early events associated with exposure to these NM. The battery of biochemical markers includes soluble molecules, antioxidant capacity, peroxidated lipids and carbonyl groups in serumproteins as a biomarkers of systemic inflammation and vascular adhesion molecules to assess endothelial activation/damage. Abnormalities in exhaled breath condensate chemistry reflecting intrinsic changes in the airway lining fluid and lung inflammation seem promising tools suitable for BM studies and are broadly discussed.