Fabrication of macroporous protein-containing films through the reverse emulsions approach featuring β-cyclodextrin-conjugated PEG-PLGA copolymers

A series of β -cyclodextrin-conjugated 4-arm poly(ethylene glycol)-poly(lactide- co -glycolide) (4-arm PEG-PLGA) copolymers were synthesized by a ring-opening polymerization of D,L-lactide and glycolide using 4-arm PEG as initiator, and then conjugated with mono(6-ethylenediamine-6-deoxy)- β -cyclodextrin (CDen) or ethylenediamino-bridged bis- β -CD (BCDen). The chemical structures of copolymers were confirmed by 1 H-NMR and FTIR spectroscopy. The β -CD-conjugated PEG-PLGA formed stable reverse micelles due to the formation of β -CD and bovine serum albumin (BSA) inclusion complexation, which could accommodate BSA in the organic solvent with improved encapsulation efficiency. Moreover, we demonstrated a one-step approach to construct macroporous protein-containing films using these reverse micelles. The films with ordered pore arrays were directly prepared from reverse micelles. Interestingly, the protein was totally located in the whole matrix except for the pores.