A facile synthesis and dual stimuli-responsive properties of BSA-based core-shell microspheres

A kind of novel thermal and pH stimuli-responsive core-shell microspheres (BSA@PVP) based on bovine serum albumin (BSA) have been synthesized via in-situ polymerization of N-vinyl pyrrolidone (NVP), and subsequent self-assembly in aqueous solution. The structure and morphology of the BSA@PVP microspheres were characterized by FT-IR, TEM and DLS. The changes of size and carried charges in response to temperature and pH value were assessed using UV-Vis spectra and DLS. The drug release behaviors were investigated under different conditions. The results indicated that the composites have core-shell structure, the diameter is about 0.15-0.35 mu m and the negative charges are carried. These microspheres exhibited a continuous controllable release of the entrapped doxorubicin hydrochloride (Dox center dot HCl) for about 50 h. They were a kind of potential dual stimuli-responsive drug carrier. BSA@PVP microspheres exhibit high release rate in acidic environment that may be helpful to achieving a required placid level and rapidly controlling illness. Accordingly, there is a lower release rate in alkaline environment, which may be conducive to avoid the sudden release and maintain plasma concentration for a long time.