Chitosan oligosaccharide/Pluronic polymer nano-aggregates (COPNs) were designed as building blocks to fabricate (heparin/chitosan)-mimetic multilayered films

and the application of the multilayered films in loading hydrophobic drugs was investigated.Sulfonated Pluronic P123 synthesized from the reaction between Pluronic P123 and 1

3-propane sultone

self-assembled with Pluronic F127 in aqueous solution to form mixed polymeric micelles with negatively charged sulfonic acid groups on the exterior.COPNs were obtained via the electrostatic interaction between chitosan oligosaccharide and the mixed polymeric micelles.The particle size analysis

zeta potential analysis and transmission electron microscopy (TEM) experiments demonstrated the formation of the mixed micelles and COPNs.The mean diameter and the zeta potential of COPNs were about (27.61 2.46) nm and (6.12 1.82) mV.The quartz crystal microbalance (QCM) experiment demonstrated that the layer-by-layer (LBL) films can be fabricated via alternating deposition of heparin and COPNs.The surface morphologies of the LBL films were analyzed using atomic force microscope (AFM)

and the AFM images demonstrated the stability of COPNs during the LBL process.The fluorescence emission spectra verified that the hydrophobic pyrene can be incorporated by pre-encapsulation in COPNs

and the amount of pyrene in the LBL films increased with respect to the increase of the number of layers of pyrene-loaded COPNs.The drug loading and release behaviors of the LBL films were investigated using puerarin as a model drug.