Abstract

Preparation of concentrated silver nanoparticles in water remains a challenge today. The intrinsic reactivity of silver, as well as the high surface energy of nanoparticles, make it difficult to handle them without altering their pristine properties. Herein, we report the preparation of concentrated silver nanoparticles (AgNPs) dispersion (2 mM; 1.5.10(15) NPs/mL) by reducing Ag+ in-situ of a beta-cyclodextrin-epichlorohydrin polymer (beta CDP) as a capping agent. The prepared nanoparticles (AgNPs@beta CDP) with a Surface Plasmon Resonance band at 396 nm, and a hydrodynamic diameter of 21.4 +/- 1.8 nm, retained both features after being precipitated and re-dispersed in water. The AgNPs core had a spherical morphology, with a 12.7 +/- 1.5 nm diameter in size, as determined by TEM. The AgNPs@beta CDP showed outstanding bactericidal properties against Escherichia coli (MIC= 0.37 nM), one of the lowest ever achieved for silver nanoparticles. We suggest that the polymer acts as a Trojan horse with AgNPs as payload.