Thermal and pH dual responsive alginate/CaCO3 hybrid membrane prepared under compressed CO2

Alginate/CaCO3 hybrid membranes with pH- and thermal-responsive drug release properties were prepared under compressed CO2 using polyacrylic acid (PAA) as a crystal growth additive. Aliphatic poly(urethane-amine) (PUA) was employed as the thermal-responsive composition in the hybrid membranes. The hybrid membranes were characterized by scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction and thermogravimetric analyzer. The interaction between PAA and aliphatic PUA contributed the formation of compact CaCO3 microparticles and the high drug loading efficiency of the hybrid membranes. By adjusting the pressure and reaction time of the biomineralization process, sustained drug release property could be achieved from the hybrid membranes. The results indicated that the compact CaCO3 microparticles could hinder the permeability of the encapsulated drug and reduce the drug release effectively. Moreover, the thermal-sensitivity of aliphatic PUA and pH-sensitivity of alginate matrix would preserve after the biomineralization process.