A novel water soluble sulfonated hyperbranched polyether (HBPO- SO3)

consisting of a hydrophobic hyperbranched poly(3-ethyl-3- oxetanemethanol) core and many sulfonate terminal groups

was designed as a promising heparin-like biomaterial.The micelle formation of the resultant HBPO-SO3 in aqueous solutions was monitored by fluorescence spectroscopy using pyrene as a hydrophobic probe

and the critical micelle concentration (CMC) was determined to be 0.017 mg/mL.The analyses of transmission electron microscopy (TEM) clearly showed that all the sulfonated hyperbranched polyether samples aggregated into spherical micelles with diameters of 25～70 nm.The mean diameter of micelles determined by the laser scattering particle size distribution analyzer is about 32.5 nm.Compared with the saline solution used as a control in the plasma recalcification time (PRT) assay

both HBPO-SO3 micelles solution and unimolecular micelles solution could reduce blood clotting.In the case of HBPO-SO3 at a concentration of 0.33 mg/mL

there were no signs of clotting even after 1 h.The toxicity of HBPO-SO3 was assessed in vitro with ECV-304 cells using MTT method and found to be nontoxic for 48 h incubation up to a 0.1 mg/mL concentration.The cell morphology was also observed by confocal laser scanning microscope (CLSM).The results of CLSM revealed that the culture media containing HBPO-SO3 up to 0.1 mg/mL had no negative effect on the attachment and proliferation of cells

compared with the control.Results from the PRT assay and cell culture declared that both HBPO-SO3 micelles and the unimolecular micelles exhibited good hemocompatibility and low cytotoxicity.These experimental results suggest that HBPO-SO3 could be a good candidate for hydrophobic drug carriers.