Nanoparticles: health effects--pros and cons

Abstract

With the advent of nanotechnology, the prospects for using engineered nanomaterials with diameters of < 100 nm in industrial applications, medical imaging, disease diagnoses, drug delivery, cancer treatment, gene therapy, and other areas have progressed rapidly. The potential for nanoparticles (NPs) in these areas is infinite, with novel new applications constantly being explored. The possible toxic health effects of these NPs associated with human exposure are unknown. Many fine particles generally considered "nuisance dusts" are likely to acquire unique surface properties when engineered to nanosize and may exhibit toxic biological effects. Consequently, the nuisance dust may be transported to distant sites and could induce adverse health effects. In addition the beneficial uses of NPs in drug delivery, cancer treatment, and gene therapy may cause unintentional human exposure. Because of our lack of knowledge about the health effects associated with NP exposure, we have an ethical duty to take precautionary measures regarding their use. In this review we highlight the possible toxic human health effects that can result from exposure to ultrafine particles (UFPs) generated by anthropogenic activities and their cardiopulmonary outcomes. The comparability of engineered NPs to UFPs suggests that the human health effects are likely to be similar. Therefore, it is prudent to elucidate their toxicologic effect to minimize occupational and environmental exposure. Highlighting the human health outcomes caused by UFPs is not intended to give a lesser importance to either the unprecedented technologic and industrial rewards of the nanotechnology or their beneficial human uses.

Figure 1

Fluorescent photostability and fluorescence intensity of quantum dots (QD 630) compared with organic dye Alexa 488. (A–E) Nuclei are labeled bright red with QD 630–streptavidin; actin fibers are stained green with Alexa 488. (F–I) Images of actin fibers are labeled red with QD 630–streptavidin; nuclei are labeled green with Alexa 488. Numbers in the bottom left corner indicate elapsed time. Scale bar, 10 μm. From Wu et al. (2003) and reproduced with permission from Quantum Dot Corp. (Hayward, CA).

Figure 2

(A,B) Spectral images of quantum dot–prostate-specific membrane antigen conjugates in live animals with and without tumor (control). (A) Image of control animals, with no fluorescence (unmixed spectral). (B) Xenograft tumor-bearing animal showing bright red fluorescence of tumor. (C) Autofluorescent superimposed image of control and tumor-bearing animals. (D) Autofluorescent unmixed quantum dot image. From Gao et al. (2004) and reproduced with permission from the Nature Publishing Group.

Figure 3

Hypothetical schema of potential interactions that may occur via inhalation of UFPs and translocation to other organs. Abbreviations: ICAM-1, intracellular adhesion molecule-1; PMNs, polymorpho-nuclear leukocytes; RNS, reactive nitrogen species; VCAM-1, vascular adhesion molecule-1. Schema also shows suspected interactions (indicated by a question mark) leading to sequences of events that may cause cardiovascular and pulmonary morbidity and mortality.