Temperature sensitive dendrite-shaped PNIPAAm/Dex-AI hybrid hydrogel particles: formulation and properties

The development of a new temperature sensitive hydrogel particle having biodegradable crosslinkages, composed of poly(N-isopropylacrylamide)/dextran-allyl isocyanate (PNIPAAm/Dex-AI) was prepared through precipitation polymerization. Dex-AI was used as a precursor as well as a biodegradable crosslinker for forming the network particles. Characterization data showed that these PNIPAAm/Dex-AI hydrogel particles had an average hydration diameter around 1.0 mm and showed a dendrite-like heterogeneous morphology with two different porous microstructures. The hydrogel particles exhibited a transition temperature or lower critical solution temperature (LCST) at around 25.7 °C through differential scanning calorimetry (DSC) measurement or temperature dependence study of particles volume. The freeze-dried particles swelled quickly when socked in distilled water at room temperature and large amounts of water were stored within the network before reaching the stable swollen state.