Science Daily recently carried this article. The increasing industrial use of nanosized silica particles has brought about a corresponding increase in questions about the possible toxic effects of these particles on human health. Currently, there is no consensus about what these effects might be. Brian Thall, a scientist at DOE’s Pacific Northwest National Laboratory, gave presentations at the 2009 AAAS annual meeting on nanosized silia particles and the cellular proteins they might attach to and use to enter a cell. http://www.sciencedaily.com/releases/2009/02/090214162629.htm