From Wikipedia: "Osmosis is the net movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration, in order to equalize the solute concentrations on the two sides." (http://en.wikipedia.org/wiki/Osmosis)
From dictionary.com: "
the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane." (http://dictionary.reference.com/browse/osmosis?s=t)
Nanoparticles would be the solute in this case. (If a foreign substance, and not water, were the solvent, you'd have problems regardless of how tiny the solent's particles were.)
From dictionary.com: " the tendency of a fluid, usually water, to pass through a semipermeable membrane into a solution where the solvent concentration is higher, thus equalizing the concentrations of materials on either side of the membrane." (http://dictionary.reference.com/browse/osmosis?s=t)
Wouldn't that include solvents other than water?