Silver Nanoparticles, cure-all or recipe for lung problems?

[Jay Reynolds]

One Man's View:

"Silver Lungs"
http://lib.store.yahoo.net/lib/realityzone/UFNsilverlungslanding.html

Features:
- Nano sized silver particles and ions produced
-How does silver work inside the body? - In lay terms, it is commonly believed that a disease-causing pathogen or a virus - in the presence of nano-sized silver particles or ions - will become suffocated through a chemical process called "Catalytic Oxidation".

VS.

One Woman's Master's Thesis:

IN VITRO TOXICITY OF SILVER NANOPARTICLES IN HUMAN LUNG EPITHELIAL CELLS
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA495861&Location=U2&doc=GetTRDoc.pdf

Abstract
Nanotechnology is quickly becoming incorporated into everyday products and uses. Silver nanoparticles, specifically, are being used in commercial products, to include aerosols. The purpose of this research was to determine whether silver nanoparticles are toxic to human lung epithelial cells. Different types (coated vs. uncoated), concentrations (10, 50, 100, and 200 μg/mL) and sizes (coated 5 and 80nm, uncoated 10 and 80nm) of silver nanoparticles were used during this study. Toxicity measurements were completed through in vitro techniques. Another study was also completed on toxicity mechanisms by measuring the reactive oxygen species (ROS) generated. Results showed that silver nanoparticles induce mitochondrial toxicity through a size and concentration dependent manner. Increasing the concentration yielded increased toxicity and the smaller the size induced increased toxicity to the mitochondria. Results also showed that the uncoated nanoparticles were also more toxic to the cells than the coated nanoparticles. The small nanoparticles (coated 5, uncoated 10nm) induced more formation of the ROS than the larger nanoparticles (80nm).

Supporting these studies is a study by Hussain et al. (2005) who looked at toxic response of silver nanoparticles (15 and 100 nm) in BRL 3A rat liver cells. They found that silver nanoparticles induce a toxic response in this cell type. Also, they determined that mitochondrial function diminished considerably in cells exposed to silver nanoparticles at 5-50 μg/mL (Hussain, Hess, Gearhart, Geiss, & Schlager, 2005). It was also determined that there was significant LDH leakage across the membrane in cells exposed to silver nanoparticles from 10-50 μg/mL (Hussain, et al., 2005). It was observed that along with the reduced mitochondrial membrane potential, there was an increase in ROS levels suggesting that the cytotoxicity of nanosilver was probably mediated through oxidative stress (Hussain, et al., 2005). Also, the team observed that there was an increase in ROS generation with an increase in nanoparticle concentration. The study showed that after an exposure of 24 hours, the cells showed a concentration dependent LDH leakage with significant cytotoxicity at 10-50 μg/mL (Hussain, et al., 2005). This team not only studied silver nanoparticles, but also other nanomaterials (MoO3, Al, Fe3O4, and TiO2). They determined through the use of MTT and LDH assays that the silver nanoparticles were more toxic than the other nanomaterials noted above.