Amphiphilic block copolymers poly(ethylene glycol)-co-poly(glycidyl methacrylate) (PEG-co-P(GMA)) were synthesized via atom transfer radical polymerization (ATRP).Postpolymerization decoration of reactive epoxy groups in the P(GMA) block with N-(3-amino propyl) imidazole (API) resulted in a new kind of water soluble copolymer PEG-P(GMA-API).The weight-average molecular weight and polydispersity of PEG-P(GMA-API) were determined to be 17175 and 1.08 with 1H-NMR and GPC

respectively.The resulted copolymers could self-assemble into spherical nano-micelles directly in an aqueous medium.The critical micellization concentration (CMC) of the micelles was 410-2 g/L

which was significantly influenced by amino and imidazole groups.Dynamic light scattering (DLS) study showed the diameter of the micelles was about 40 nm and the micelle surface was always positively charged when the pH of the solution increased from 4 to 9.The resulted nano-micelles had the capacity to encapsulate hemoglobin (Hb) in aqueous solution with the encapsulation efficiency of 32.4 wt% at pH 7.4.The features of Hb-based micelles were spherical with a diameter of 40 nm

which was larger than that of blank micelles (30 nm).The Hb-based micelles displayed a reversible change in the UV-Visible absorption spectrum from the deoxy form to the oxygen-binding one

in response to the partial oxygen pressure of the atmosphere.The characteristic absorption peaks of the encapsulated Hb in different gas-binding states showed no significant change comparing with those of the free Hb.The Hb encapsulated PEG-P(GMA-API)nano-micelles showed the potential application as artificial oxygen carriers for transfusion.