On the basis of the preparation of water-soluble Au nanoparticles protected with methoxypolyethylene glycol-poly(ε-caprolactone) block copolymer end-capped with α-thioctate ester (MPEG-PCL- ALA), hybrid supramolecular hydrogels were fabricated by the inclusion complexation between MPEG-PCL monolayer-protected Au nanoparticles and α-cyclodextrin (α-CD) in aqueous solution. TEM photograph showed that the size of gold nanoparticles was about 6～8 nm. XRD results confirmed that there existed the characteristic peak (2θ＝19.7°) of polypseudorotaxanes formed from MPEG-PCL block copolymer with α-CD in as-obtained hydrogels. UV-visible spectra displayed that the surface plasma resonance absorption peaks appeared at about 525 nm for both aqueous solution of monolayer-protected Au nanoparticle and its hydrogel with α-CD, and there is no shift of the surface plasma resonance absorption peak after three-month storage of its aqueous solution, showing a good colloidal stability.

Key words: monolayer-protected Au nanoparticle, cyclodextrin, inclusion complexation, supramolecular hydrogel, surface plasma resonance