NOVELTY - Production of silver nanoparticles involves mixing a silver salt and a reducing agent (I), and forming silver nanoparticles by reducing the silver salt using the reducing agent.    USE - Production of silver nanoparticles e.g. polysaccharide-coated silver nanoparticles used for preparation of hydrogel particles and microparticles used for products e.g. skin scrub and defoliate agent used for treatment of acne or wound, toothpaste, dietary supplement, mouthwash used for detection of X-ray image of tooth in patients mouth, toothpick, floss product, fungal treatment product, deodorant, and bandage, and preparation of wound dressing (all claimed), and in metal-film plasmonic solar cell.    ADVANTAGE - The method enables the production of silver nanoparticles with excellent antimicrobial effect, and optical and electrical properties, and provides the solar cells with excellent solar energy conversion efficiency.    DETAILED DESCRIPTION - Production of silver nanoparticles involves mixing a silver salt and a reducing agent of formula (I), and forming silver nanoparticles by reducing the silver salt using the reducing agent.    R=H, hydroxy, methyl, carboxy, amide, or group chosen from group of formulae (ii)-(iv);and    n=positive integer.    INDEPENDENT CLAIMS are included for the following:    (1) preparation of hydrogel particles, which involves forming an emulsion using an oil phase and an aqueous phase comprising silver nanoparticles and polysaccharides, stirring the formed emulsion at a reduced temperature, and preparing hydrogel particles containing silver nanoparticles from the aqueous phase;    (2) microparticles, which are obtained by coating using the silver nanoparticles. The microparticles have a diameter of 10-100 mu m;    (3) production of polysaccharide-coated silver nanoparticles, which involves preparing a solution containing suspended silver nanoparticles and stabilizing agent, and replacing the stabilizing agent using polysaccharides;    (4) acne or wound treatment product, which contains the silver nanoparticles;    (5) treatment of acnes, which involves applying the silver nanoparticles on the acnes;    (6) skin scrub or defoliate agent, which contains the microparticles;    (7) toothpaste, which contains 10-100 ppm silver nanoparticles and 0.1-0.5% sodium fluoride;    (8) mouthwash, which contains 10 ppm or more silver nanoparticles;    (9) dietary supplement, which contains the silver nanoparticles;    (10) toothpick, which is obtained by coating using the silver nanoparticles;    (11) floss product, which is obtained by coating using the silver nanoparticles;    (12) fungal treatment product, which contains the silver nanoparticles suspended in a citrate solution;    (13) deodorant, which contains the silver nanoparticles suspended in a citrate solution;    (14) bandage, which consists of a non-adhesive absorbent pad containing embedded silver nanoparticles; and    (15) preparation of wound dressing, which involves providing a fabric having positive charge, soaking the fabric in a suspension containing silver nanoparticles, washing the fabric using water, and drying the fabric.