Two NIOSH researchers recently theorized about the possible adverse health effects of nanoparticles in the December 2006 edition of Environmental Health Perspectives. I list the scientists’ "pros" and "cons" and some of the literature upon which the scientists rely below.

Near the end of the article, the authors present a table of hypothetical adverse health effects which might accompany the translocation of nanoparticles throughout the human body after inhalation and/or dermal exposure. While the table is useful for discussion purposes (and the authors make it clear that it is based on current limited toxicology studies and human data), a tremendous amount of research is still needed to determine whether the table approaches reality. 

The authors conclude with the following thoughts:

". . . the benefits of nanotechnology dominate our thinking, the potential for undesirable human health outcomes should not be overlooked . . . Development of safety guidelines by government for the nanotechnology industries, including manufacturing, monitoring of worker exposure, ambient release of [nanoparticles], and risk examinations, is mandatory to promote nanotechnology for its economic incentives and medicinal applications.  

M. R. Gwinn, et al., “Nanoparticles: health effects–pros and cons,” Environ Health Perspectives, Vol. 114, No. 12 (Dec. 2006).

PROS:

I. Use of nanoparticles as fluorescent biological in vivo probes in medical imaging and diagnostics.

A. M. Burches, et al., “Semiconductor nanocrystals as fluorescent biological labels,” Science, 281 (5385): 2013-2016 (1998).

B. X. Wu, et al., “Immunofluorescent labeling of cancer marker. Her2 and other cellular targets with. semiconductor quantum dots,” Nature Biotechnology, 21(1):41-46 (2003).

C. Y. Zhang, et al., "Surface modification of superparamagnetic magnetite nanoparticles and their intracellular uptake," Biomaterials 23 (7), 1553-1561 (2002).

D. X. Gao, et al., “In vivo cancer targeting and imaging with semiconductor quantum dots,” Nature Biotechnology, 22(8):969-976 (2004).

II. Use of nanoparticles in targeted encapsulated drug delivery. 

 A. S. M. Moghimi, et al., “Nanomedicine: current status and future prospects,” The FASEB Journal, 19(3):311-331 (2005).

B. T. Allen, et al., “Drug delivery systems: entering the mainstream,” Science, 303:1818-1824 (2004).

C. M. Kumar, et al., “Cationic Poly(lactide-co-glycolide) Nanoparticles as Efficient in vivo Gene Transfection Agents,” Journal of Nanoscience and Nanotechnology, 4(8):990-994 (2004).

D. S. Gelperina, et al., “The Potential Advantages of Nanoparticle Drug Delivery Systems in Chemotherapy of Tuberculosis,” Am J Respir Crit Care Med, 172(12):1487–1490 (2005).

III. Use of nanoparticles in anti-cancer treatment to specifically target tumor cells.

A. D. O’Neal, et al., “Photo-thermal tumor ablation in mice using near infrared-absorbing nanoparticles,” Cancer Letters, 209(2): 171–176 (2004).

B. J. M. Perkel, “The Ups and Downs of Nanobiotech,” The Scientist, 18(16):14-18(2004).

C. S. Denardo, et al., “Development of tumor targeting bioprobes,” Clin. Cancer Research, 11(19 pt 2): 7087s-7092s (2005).

D. I. H. El-Sayed, et al., "Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles,” Cancer Letters, 239(1):129-135 (2006).

E. T. Andresen, "Enzymatic release of antitumor ether lipids by specific phospholipase A2 activation of liposome-forming prodrugs,” Journal of Medicinal Chemistry, 47(7):1694-703 (2004).

IV. Use of nanoparticles in gene therapy.

A. B Gopalan, et al., “Nanoparticle based systemic gene therapy for lung cancer: molecular mechanisms and strategies to suppress nanoparticle-mediated inflammatory response,” Technology Cancer Research Treatments, 3(6):647-57 (2004).

B. S. Mansouri, et al., “Characterization of folate-chitosan-DNA nanoparticles for gene therapy,” Biomaterials, 27(9):2060-2065 (2006).

C. Z. Li, et al., “Poly-L-lysine-modified silica nanoparticles: a potential oral gene delivery system,” Journal of Nanoscience and Nanotechnology, 5(8):119-1203 (2005).

D. C. Dufes, et al., “Synthetic anticancer gene medicine exploits intrinsic antitumor activity of cationic vector to cure established tumors,” Cancer Research, 65(18):8079-8084 (2005).

E. S. Prabha, et al., “Nano-particle-medicated wild-type p53 gene delivery results,” Molecular Pharmacology, 1(3):211-216 (2004).

F. D. Bharali, et al., “Organically modified silica nanoparticles: a nonviral vector for in vivo gene delivery and expression in the brain,” Proceedings of the National Academy of Sciences, 102(32):11539-11544 (2005).

CONS:

I. Morbidity and Mortality Due to Cardiovascular affects.

Analogy drawn from existing air pollution and ultra-fine particle studies.

II. Pulmonary Morbidity and Mortality.

Analogy drawn from existing air pollution and ultra-fine particle studies. Additionally:

A. C. Lam, et al., “Pulmonary Toxicity of Single-Wall Carbon Nanotubes in Mice 7 and 90 Days After Intratracheal Instillation,” Toxicological Sciences, 77(1):126-134 (2004).

 B. A. Shvedova, et al., “Unusual inflammatory and fibrogenic pulmonary responses to single-walled carbon nanotubes in mice,” American Journal of Physiology – Lung Cellular and Molecular Physiology, 289(5):L698-L708 (2005).

C. D. Warheit, et al., “Comparative Pulmonary Toxicity Assessment of Single Wall Carbon Nanotubes in Rats,” Toxicological Sciences, 77(1)117-125 (2004).

III. Translocation and Toxicity to Other Organs.

Analogy drawn from existing ultra-fine particle studies.

IV. Neuronal translocation.

Analogy drawn from existing ultra-fine carbon black study.

V. Dermal Exposure and translocation.

Analogy drawn from existing studies concerning skin penetration of micronized particles.