Metal NPs have extensive applications in biotechnology, drug and gene delivery, and medical imaging due to their unique characteristics. For example, metal NPs are often used in electronic wiring in medical devices, since the boiling point lowers and mechanical …show more content…
Rats exposed to silver (Ag) NPs for 12 weeks had increased perivascular inflammation as well as chronic alveolar inflammation, alveolar wall thickening and swelling, granulomatous lesions, and alveolar macrophage accumulation (Cho et al, 2003). A parallel study found the same type of lung damage accompanied by a decrease in lung function, indicated by the tidal volume, minute volume, and peak inspiratory flow, which persisted throughout a 12-week recovery period (Song et al, …show more content…
Asthma is an allergic inflammatory disease of the airways characterized by airway hyperresponsiveness (AHR), airway epithelia remodeling, and eosinophil infiltration. In an asthmatic, inhaled allergens interact with Th2 cells and IgE bound to the surface of mast cells, which are interspersed among the bronchial epithelial cells. Activated Th2 and mast cells release chemical mediators of type I hypersensitivity reactions, cytokines, and chemotactic factors, and smooth muscle contraction, mucous secretion, and increased vascular permeability and edema ensue. Release of inflammatory mediators from eosinophils aggravate bronchoconstriction and edema, impairs mucociliary function, and damages epithelial cells. Epithelial cell damage further stimulates nerve endings in the mucosa, which initiates an autonomic response resulting in airway narrowing and mucus secretion (Li et al,