Oriented Assembly of Zinc Oxide Mesocrystal in Chitosan and Applications for Glucose Biosensors

By imitating biomineralization, a facile synthetic method to fabricate oriented self-assembly zinc oxide mesocrystal in chitosan (CS-ZnO) with different morphology is presented. Chitosan acts as a structure-directing agent to guide the formation of ZnO nuclei and the self-assembled preferential growth from small building units to larger structures through Coulomb forces and the adjustment of surface energy. The prepared CS-ZnO mesocrystals have been successfully used in the glucose sensors. The products obtained were characterized with field emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and energy dispersive X-ray spectroscopy. By comparing the sensitivities of biosensors fabricated by different shaped CS-ZnO structures, the starfish-like CS-ZnO mesocrystal with a gain size of 20-30 nm showed a better sensing performance due to its mesocrystal structure, good biocompatibility, and specific architecture.