Elechiguerra JL, Burt JL, Morones JR, et al. Interaction of silver nanoparticles with HIV-1. Journal of Nanobiotechnology. 2005;3:6. doi:10.1186/1477-3155-3-6.35 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1190212/

From this study you linked, here's the conclusion paragraph in the abstract.

"The interactions of inorganic nanoparticles with biosystems are just beginning to be understood, and potential applications are being discovered at an increasing rate. However, in order to realize the future promise of nanoscience, it is imperative that the toxicity and long-term health effects of exposure to nanomaterials be fully explored. "