Potential toxicity and safety evaluation of nanomaterials for the respiratory system and lung cancer

Figures & data

Table 1 Particles with proven lung carcinogenic effects in animals and/or humans (most of the classifications are also classified by the International Agency for Research on Cancer, IARC)

Metal oxides, mineral fibers, particles, and fine and superfine particles	Source	Exposure, rat and human (IARC)
Particulate matter (PM0.1, PM2.5, PM10)	Ambient, inhalable air pollutants	Possibly carcinogenic? (unknown fraction)
NiO	Exhaust	+ (positive, carcinogenic)
Quartz (crystalline silica)	Constructions	+ (positive, carcinogenic)
Asbestos insulation	Mining	+ (positive, carcinogenic)
Carbon black	Pigments, toner, tires	+ (possibly carcinogenic)
Refractory ceramic fibers	Insulation	+ (possibly carcinogenic)
Wood dust	Furniture, making, saw mills	± carcinogenic (some types)
TiO2	Pigments, sunscreens	+ (positive, animals)
Diesel exhaust	Vehicular engines, cars	+ (positive, carcinogenic)
Talc	Cosmetics, mining	+ (positive, only animals)
Volcanic fly ash	Ambient	+ (positive, only animals)
Coal mine dust, graphite, cement	Mining, occupational, paints, construction	Not classifiable
Iron oxides	Pigments, paramagnetic, diagnostics	± (mixed results)

Abbreviations: NiO, nickel oxide; TiO₂, titanium dioxide.

Notes: Particulate matter size is given in nm (0.1, 2.5, and 10 nm) Data from Knaapen et al.³¹ Adapted with permission from Borm PJ, Schins RP, Albrecht C. Inhaled particles and lung cancer, part B: paradigms and risk assessment. Int J Cancer. 2004;110(1):3–14.³²

Table 2 Similarities and differences of coarse particles, microparticles, fine particles, and ultrafine and ENPs

Physical and chemical characteristics	Coarse particles	Microparticles	Fine particles	Ultrafine and ENPs
Size (examples: hair =60 µm; lung alveoli =400 µm; C60 =1 nm)	1–2 mm very coarse sand 125–250 µm fine sand (size: 100,000–10,000 nm)	10–100 µm Ceramics, glass, metals 0.3–300 µm Asbestos, minerals, fibers 1–100 µm fly ash (size: 10,000–2,500 nm)	0.01–2.5 µm Tobacco smoke 0.01–1 µm Soot 0.01–0.5 µm PM2.5=2.5 µm (size 2,500–100 nm)	Ultrafine particles <0.1 µm (aggregates) ENPs 1 × 10^−9–1 × 10^−7 nm 1–100 nm Nanopowders agglomerates, nanocrystals
Chemical composition	SiO2, metal salts, mineral dusts, etc	Varied, metal oxides, mineral salts, several constituent dusts	Multiple components, PAHs, organics, inorganics	Single constituent material, or a composition of several clean materials
Shape and surface	Atoms at surface insignificant in relation to bulk mass	Various shapes, crystalline	Various shapes, porous surfaces	Smooth property scaling Large surface area and high particle number per unit mass
Solubility	Insoluble Low solubility Sparingly soluble	Insoluble, low solubility	Low solubility or insoluble	ENPs might aggregate into vastly different shapes. Sizes affect solubility They are slightly soluble and insoluble in water Interaction of ENPs with solvent
Optical properties, photoactivity	Refractive index Light scattering	Light scattering	Light scattering	Unexpected optical characteristics, quantum effects Photoactivity, phototoxicity
Quantum dot effect	–	–	–	Discontinuous behavior due to quantum confinement effects in materials. These factors affect the chemical reactivity of ENMs

Abbreviations: ENMs, engineered nanomaterials; ENPs, engineered nanoparticles; PAHs, polycyclic aromatic hydrocarbons; SiO₂, silicon dioxide.

Figure 1 Comparative sizes for (from left to right) human hair (60 μm diameter), spherical microparticle of the same diameter, 1 million particles 600 nm diameter, and 1 billion nanoparticles of 60 nm diameter.

The article/figure is published under Creative Commons License 2.0 CC-BY.38.

Note: Reproduced from Buzea C, Pacheco II, Robbie K. Nanomaterials and nanoparticles: sources and toxicity. Biointerphases. 2007;2(4):MR17–MR71.⁴²

KnaapenAMBormPJAlbrechtCSchinsRPInhaled particles and lung cancer. Part A: mechanismsInt J Cancer2004109679980915027112

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BormPJSchinsRPAlbrechtCInhaled particles and lung cancer, part B: paradigms and risk assessmentInt J Cancer2004110131415054863

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BuzeaCPachecoIIRobbieKNanomaterials and nanoparticles: sources and toxicityBiointerphases200724MR17MR7120419892

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