Metallization of DNA hydrogel: application of soft matter host for preparation and nesting of catalytic nanoparticles

Nanoparticles (NPs) of Au, Ag, Pt, Pd, Cu and Ni of 2-3 nm average-size and narrow-size distributions were synthesized in DNA cross-linked hydrogels by reducing corresponding metal precursors by sodium borohydride. DNA hydrogel plays a role of a universal reactor in which the reduction of metal precursor results in the formation of 2-3 nm ultrafine metal NPs regardless of metal used. Hydrogels metallized with various metals showed catalytic activity in the reduction of nitroaromatic compounds, and the catalytic activity of metallized hydrogels changed as follows: Pd > Ag approximate to Au approximate to Cu > - Ni > Pt. DNA hydrogel-based soft catalysts'' elaborated in this study are promising for green organic synthesis in aqueous media as well as for biomedical in vivo applications.