[en] The structure of C_1_2-3.0GEMA (where C_1_2 is a dodecyl group and GEMA is glucosyloxyethyl methacrylate) aggregates and gold nanoparticles (AuNPs) stabilized by C_1_2-3.0GEMA were studied by SANS, SAXS, TEM, and EXAFS analysis. SANS results revealed that the C_1_2-3.0GEMA aggregates formed spherical (or ellipsoidal) micelles in aqueous solution. The overall radius of these micelles was estimated to be 23.9 Å. SAXS and TEM analyses showed that the average radius of the AuNPs is about 17.5 Å. EXAFS analysis suggested that the sulfur atom of C_1_2-3.0GEMA was coordinated to the surface of the AuNPs. Therefore, C_1_2-3.0GEMA directly interacted with gold atoms and the interaction leads to the formation of small size AuNPs. These results suggest that C_1_2-3.0GEMA aggregates can prevent the formation of large AuNPs. In other words, the C_1_2-3.0GEMA molecules surround the surface of the nanoparticles for increasing their stability. (author)