Chaperones are defined as a family of protein that mediates the correct assembly of other polypeptides but that are not components of the functional assembled structures. In this work, we have devised a novel method in which alpha-cyclodextrins (alpha-CDs), "artificial chaperones", facilitate block copolymers self-assembling into the expected structure. Poly(ethylene oxide)-b-poly(4-vinylpyridine) (PEO45-b-P4VP(70)) is first threaded by alpha-CDs, leading to the formation of metastable micelles. After stabilizing the metastable micelles by shell cross-linking with poly(ethylene oxide)-b-poly(acrylic acid) (PEO114-b-PAA(50)), alpha-CDs are removed and the expected structure, polymeric vesicle, is achieved. On the contrary, only spherical micelles are formed in the similar conditions without the assistance of alpha-CD. Therefore, alpha-CDs, which act as chaperones, guide the self-assembly of block copolymers in the expected pathway. (C) 2008 Elsevier Ltd. All rights reserved.