3.1. Changes upon metal incorporation
The formation of CuNPs and AgNPs dispersed into polyol-modified matrices was illustrated by marked color changes. The most visible changes took place from blue to black and accounts for Cu2+conversion into Cu0 in the presence of NaBH4 as a reduction agent. However, a less visible color change was noticed for Ag+ conversion into Ag0 in the solution (Fig. S4.a) . These changes are much more pronounced in dry powders of H20@NaMt modified by Cu0 and Ag0 and their cationic forms (Fig. S4.b ). The same results were observed for similar metal insertion in the presence of H20@CT-based samples. (Fig. S5).
Metal incorporation was confirmed by visible modification of the morphology of surface of the host-material. Preliminary observation through optical microscopy revealed a transition from a clean and almost soft surface of NaMt to the appearance of grains on the surfaces of both Cu0/ NaMt and Ag0/ NaMt (Fig. S6 ). This provides evidence of the formation of metal particles. Similar observations were made on CT-based materials (Fig. S7 ). This was confirmed by additional analysis through of SEM images of MNP-loaded NaMt and H20@CT (Fig. 1.a) . The appearance of grains smaller than 100 nm indicates that metal salt reduction using NaBH4 effectively produced spheroidal nanoparticles with and without polyol as dispersing agent, as illustrated by the behavior of NaMt alone and H20-coated CT material. This can also be seen with CT alone (Fig. S8). The SEM images of NaMt showed specific morphology changes of lamellar structure according to the metal inserted (Fig. 1.a ). Larger crystalline rods were observed on NaMt-Cu, presumably due to residual Cu2+ salt.