Abstract: A marker for protection valuable liquid and solid materials comprising organic or nonoraganic liquid solvents as dispersed medium, surface active substances on nanomaker, characterized in that nanomarker is a homogeneous mixture of two or more different nanoluminophors, favourable chosen from metals, nanocrystalline metal oxides -A2O3, -granates-A3B5O12, per-ovskites-AB03, spinels-AB2O4 or stoichiometric compounds with large concentrations of optically active ions like fluorides, oxy-chlorides and others.

Abstract: The present invention provides a method for imaging a biological specimen using non-linear optical properties of certain materials. The method comprises the steps of providing an aqueous dispersion of ZnO nanocrystals; contacting a biological specimen with an aqueous dispersion comprising ZnO nanocrystals; exposing the biological specimen to input electromagnetic radiation having a wavelength of from 600 to 1500 nm; recording the nonlinear output electromagnetic radiation; and generating an image of the biological specimen based on the nonlinear output radiation.