Patent ID: 7601391

Claim:
A method of preparing an organic-inorganic composite material containing a single nanoparticle therein, comprising the steps of: 1) preparing hydrophilic nanoparticles by conjugating a surface of a core or core/shell inorganic nanoparticle to an organic substance having a thiol group and a hydrophilic amine group, the surface of the inorganic nanoparticle comprising a metallic element and being protected by a surfactant, said conjugation comprising formation of a metal-thiolate (M-S) bond between the metallic element of the inorganic nanoparticle and the thiol group of the organic substance; 2) individually dispersing the hydrophilic nanoparticles by diluting the hydrophilic nanoparticles to a concentration of 2×10 −6 M or less within 10 hours after step 1) and treating the diluted hydrophilic nanoparticles in a sonication bath; and 3) forming an organic-inorganic composite material containing a single nanoparticle therein by conjugating a biopolymer to the individually dispersed nanoparticles, said conjugation comprising formation of amide bonds between the biopolymer and the amine groups of the organic substance during treatment in a sonication bath.