Development of Thermoregulatory Enzyme Carriers Based on Microencapsulated n-Docosane Phase Change Material for Biocatalytic Enhancement of Amylases

摘要

A phase change materials (PCMs)-based magnetic microcapsule system was designed as thermoregulatory enzyme carriers and then successfully constructed by microencapsulating n-docosane into an Fe3O4/SiO2 hybrid shell through interfacial polycondensation in a Pickering emulsion templating system. Scanning and transmission electron microscopic observations indicated that the as-synthesized microcapsules presented a well-defined core-shell microstructure as well as a regular spherical morphology, and their chemical structure and composition were confirmed by a series of spectroscopic characterizations. a-Amylase as a model enzyme was also successfully immobilized on the aldehyde-functionalized surface of as-synthesized microcapsules through covalent bonding. Such covalent immobilization was confirmed by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Thermal analysis results indicated that the a-amylase-immobilized microcapsules obtained a high latent heat-storage capability of approximately 155 J/g and a high encapsulation efficiency of 58%, and they also showed an effective thermoregulation capability and good thermal management performance. Most of all, the a-amylase immobilized on the microcapsules demonstrated a higher enzyme activity, thermal stability, and storage stability than that on the classical SiO2 solid carriers under the fluctuation of ambient temperature. In addition, the a-amylase-immobilized microcapsules also achieved a good separability and reusability due to its superparamagnetic nature. With an enhanced biocatalytic activity, the thermoregulatory enzyme carriers developed by this work exhibit a great potential for biologic applications and can well serve for sustainable chemistry and green processes.