PROBLEM TO BE SOLVED: To provide an inexpensive composite of a nucleic acid and silver which has a particle size of nanometer size and a high content of silver, and a dispersion of silver fine particles with high dispersion stability.SOLUTION: A solution including 10-100 mM of a silver ion is mixed with a solution including DNA comprising 60-300 bases, and then reduced to prepare the dispersion of silver fine particles so that concentration of the silver fine particle is 0.1-5 mass%. Then the composite of the silver fine particle and the DNA is obtained, wherein the silver content is 70 mass% or more per dry weight, and the diameter is 0.5-50 nm.COPYRIGHT: (C)2013,JPO&INPIT【課題】粒子径がナノメートルサイズであり、且つ、銀を高含有する、安価な核酸と銀との複合体や、分散安定性の高い銀微粒子分散液を提供すること。【解決手段】10~100mMの銀イオンを含む溶液と60個~300個の塩基からなるDNAを含む溶液を混合した後、還元して、銀微粒子濃度が0.1~5質量%となるように銀微粒子分散液を調製し、銀含有量が乾燥重量あたり70質量%以上の、直径が0.5nm~50nmである銀微粒子とDNAの複合体を得る。【選択図】なし
