TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Material: The substrate is a ceramic.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The substrate is a semiconductor, or a metal. The first metal salt comprises zinc, nickel, cobalt, iron, or preferably copper. The first metal salt is nitrate, sulfate, or chloride. The reducing agent is sodium borohydride. The second metal salt comprises silver, gold, palladium, or platinum. The second metal salt is a nitrate, a sulfate, a carbonate, or an oxide. Preferred Property: The continuous shell protects the first metal atoms from oxidation at less than 150 degrees C. The shell has an average thickness of 0.5-10 nm. The multi-metallic nanoparticles have an average diameter of 5-300 nm. The first metal nanoparticles have a diameter of 5-300 (50-150) nm. Preferred Ratio: The ratio of the first metal and the second metal is 0.005-2.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The composition comprises a dispersion stabilizer with an adjustable charge. The dispersion stabilizer comprises a net negative or net positive charge. Carboxyl groups in the stabilizer contribute to the net negative charge. Amine groups in the stabilizer contribute to the net positive charge. The kit comprises 1-80 wt.% aqueous liquid vehicle, and a flocculant. The reducing agent is hydrazine hydrate, sodium formaldehyde sulfoxilate, ascorbic acid, or sodium ascorbate. The first metal salt and the second metal comprise an acetate. The stabilizing agent has carboxylic groups. Preferred Property: The dispersion stabilizer is capable of enabling flocculation under certain conditions. The dispersion has a viscosity of not greater than 200 (preferably not greater than 15) cPs at room temperature. The reducing agent has a reduction potential of lesser than 0 V.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The substrate is a plastic. Preferred Component: The stabilizing agent comprises a water soluble polymer, or a surfactant. The water soluble polymer is a polyelectrolyte. The polyelectrolyte is polyacrylic acid, polyacrylic acid sodium salt, polycarboxylate ethers, polyimine, polydiallyldimethyl ammonium chloride, polyvinylpyrrolidone, proteins and polypyrrole, or polysaccharides. Preferred Ratio: A weight ratio of the stabilizing agent to the first metal is 0.01-2.    TECHNOLOGY FOCUS - TEXTILES AND PAPER - Preferred Material: The substrate is paper. EXAMPLE - An ink was prepared by resuspending a pellet of copper-silver core-shell nanoparticles at 5-80 wt.% by adding distilled water. The pH was adjusted to by adding 2-amino-2-methyl-1-propanol and 0.05-0.1 wt.% BYK 348 (RTM: polyether modified dimethylpolysiloxane) to adjust surface tension. The obtained formulation was treated in an ultrasonic bath for 10 minutes to disperse the nanoparticles. Results showed that the copper-silver core-shell nanoparticles in aqueous medium are rendered suitable for use ink-jet ink by addition of surfactants and/or additional polymers including binders, rheology modifiers, humectants, cosolvents, buffering agents, antimicrobial agents, and/or defoamers.