Based on hyperbranched polyglycerol (PG), a route to prepare particles with a novel topology was developed. The hydroxyls of PG were converted to trithio-carbonates, and the latter were used to mediate the surface graft polymerization of N,N-dimethylaminoethyl acrylate. The poly(NN-dimethylaminoethyl acrylate) shell was crosslinked by 1,6-dibromohexane and then parted from the core by the cleavage of trithiocarbonates with sodium borohydride. Novel particles with thiol groups located on the interface between the PG core and poly(NN-dimethylaminoethyl acrylate) shell were thus formed. The shell crosslinking could be performed at very high solid contents (2-4%). These polymer particles showed pH- and temperature-dependent solubility. (c) 2005 Wiley Periodicals, Inc.