earticle

영어

Squids and Hydroids utilize organic biopolymers as building blocks to form their load-bearing tissues. These polymeric tissues are appealing for their unusual physical and mechanical properties, including high hardness and stiffness, toughness, and low density. Here, the biochemical structure and composition of the hydroid perisarc of Aglaophenia latirostris Nutting, 1900, were investigated. Chitin, protein, and melanin, were found to represent 10, 17 and 60 wt% of the perisarc, respectively. Interestingly, similar to the adhesive and coating of marine mussel byssus, a DOPA (3, 4-dihydroxyphenylalanine) containing protein and iron were detected in the perisarc. A resonance Raman microprobe analysis of perisarc indicates the presence of DOPA-iron (III) complexes in situ, but it remains to be determined whether the DOPA-iron (III) interaction plays a cohesive role in holding the protein, chitin and melanin networks together. We also designed a method to improve the mechanical properties of chitosan in wet conditions and minimized the swelling behavior of chitosan film due to water adsorption by mimicking the sclerotization of hydroid perisarc and squid beaks, i.e., catechol-meditated cross-linking. The biomimetic chitosan composite film was prepared by mixing chitosan with L-3,4-dihydroxyphenylalanine (DOPA) as a catecholic cross-linker and sodium periodate as an oxidant. The catechol-meditated cross-linking provided a 7-fold enhancement in the stiffness in wet conditions compared to pure chitosan films and reduced the swelling behavior of the chitosan film. This strategy expands the possible applications for the use of chitosan composites as load-bearing biomaterials.