Furuzono et al. 100 nm 10 nm (a)(b)(c) Fig. 1S TEM images of Ag nanoparticles prepared at different CDT concentrations: (a) CDT-Ag1; (b) CDT-Ag2 ; and (c) CDT-Ag3. The insets show higher magnification images. Supplementary data:

Fig. 2S Antimicrobial activity of Ag nanoparticles coated with different concentrations of CDT against Escherichia coli. After mixing E. coli and Ag nanoparticles, indicated by CDT-Ag1-3, 20 µl of reactions were sampled at 0-2 hours shown at the top of each photo. Control means no addition of Ag materials, and free CDT means addition of CDT regent without Ag. Samples and seven ten-fold serial dilutions are illustrated by numbers ①～⑧, for instance, each sample shown by ① should contain 1.4 x 10 3 E. coli cells if no antimicrobial activities were presented. Furuzono et al. Control CDT-Ag1 CDT-Ag2 CDT-Ag3 2.0 h 1.0 h0.5 h 0 h Free-CDT ① ② ③ ④ ⑤ ~ ⑧ Time Dilution Supplementary data:

Ag + water toluene S COOH S S Ag + water toluene S COOH S S Ag + toluene S COOH S S Ag + toluene Ag S COOH S S S HOOC S S COOH S S HOOC NaBH 4 S COOH Ag S HOOC S COOH S S S S HOOC S Furuzono et al. Fig. 3S Schematic presentation of the synthesis mechanism of CDT-Ag nanoparticles by two-phase reduction system. Ag ions in water phase were transferred into the oil phase by TOAB. water CDTs were bonded with Ag ions. Ag ions were reduced to metallic Ag. Separation, evaporation and purification CDT-Ag nanoparticle TOABCDT S COOH Ag + Ag ion The solution mixtures were separated into two phases. Supplementary data: