Assembly of environmental sensitive microcapsules of PNIPAAm and alginate acid and their application in drug release

The objective of this research was to fabricate stable and environmentally sensitive (PNIPAAm/ALG)(n) microcapsules via layer-by-layer (LbL) technique. The structure, thermosensitive and pH-sensitive properties of the microcapsules were characterized by transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM), individually. MnCO3 microparticles and melamine formaldehyde (MF) microparticles were used as templates separately. The microcapsules from MnCO3 cores were stable over a large pH range with thermosensitive and pH-sensitive properties, while those from MF particles were unstable in basic solutions. To the end, ALG and PNIPAAm were adsorbed on recrystallized taxol alternatively, which obviously prolonged the release time of taxol above lower crystal Solution temperature (LCST) of PNIPAAm. (c) 2008 Elsevier Inc. Ail rights reserved.