Poriferan chitin as a template for hydrothermal zirconia deposition

Chitin is a thermostable biopolymer found in various inorganic-organic skeletal structures of numerous invertebrates including sponges （Porifera）. The occurrence of chitin within calcium- and silica-based biominerals in organisms living in extreme natural conditions has inspired development of new （extreme biomimetic） synthesis route of chitin-based hybrid materials in vitro. Here, we show for the first time that 3D-a-chitin scaffolds isolated from skeletons of the marine sponge Aplysina aerophoba can be effectively mineralized under hydrothermal conditions （150℃） using ammonium zirconium（IV） carbonate as a precursor of zirconia. Obtained chitin-ZrO2 hybrid materials were characterized by FT-IR, SEM, HRTEM, as well as light and confocal laser microscopy. We suggest that formation of chitin-ZrO2 hybrids occurs due to hydrogen bonds between chitin and ZrO2.