A new chitosan/sponge chitin – based membrane (CS/CH membrane) was prepared via the casting method for the first time. We used the demineralized skeleton of the marine demosponge Ianthella basta as a source for a chitinous network. The obtained membrane was immersed in 1 M LiOAc (lithium acetate) solution and tested in an Electric Double Layer Capacitor (EDLC) cell. For comparison, chitosan (CS) with LiOAc solution was also tested. The studies performed indicated good properties of the CS/CH membrane. Very good mechanical stability (for use in electrochemical capacitors) and electrochemical properties of the CS membrane were achieved by the addition of chitin isolated from the sponge to the polymer matrix. Their electrochemical performances were tested in EDLC cells by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge. The specific capacitances of the tested capacitor cells were found to be approximately 97 F g⁻¹ and 88 F g⁻¹ with CS/CH and CS membranes (in the voltage range 0–0.8 V), respectively.

The development of novel and effective methods for the isolation of chitin, which remains one of the fundamental aminopolysaccharides within skeletal structures of diverse marine invertebrates, is still relevant. In contrast to numerous studies on chitin extraction from crustaceans, mollusks and sponges, there are only a few reports concerning its isolation from corals, and especially black corals (Antipatharia). In this work, we report the stepwise isolation and identification of chitin from Cirrhipathes sp. (Antipatharia, Antipathidae) for the first time. The proposed method, aiming at the extraction of the chitinous scaffold from the skeleton of black coral species, combined a well-known chemical treatment with in situ electrolysis, using a concentrated Na₂SO₄ aqueous solution as the electrolyte. This novel method allows the isolation of α-chitin in the form of a microporous membrane-like material. Moreover, the extracted chitinous scaffold, with a well-preserved, unique pore distribution, has been extracted in an astoundingly short time (12 h) compared to the earlier reported attempts at chitin isolation from Antipatharia corals.

Three-dimensional (3D) biopolymer-based scaffolds including chitinous matrices have been widely used for tissue engineering, regenerative medicine and other modern interdisciplinary fields including extreme biomimetics. In this study, we introduce a novel, electrochemically assisted method for 3D chitin scaffolds isolation from the cultivated marine demospongeAplysina aerophobawhich consists of three main steps: (1) decellularization, (2) decalcification and (3) main deproteinization along with desilicification and depigmentation. For the first time, the obtained electrochemically isolated 3D chitinous scaffolds have been further biomineralized ex vivo using hemolymph ofCornu aspersumedible snail aimed to generate calcium carbonates-based layered biomimetic scaffolds. The analysis of prior to, during and post-electrochemical isolation samples as well as samples treated with molluscan hemolymph was conducted employing analytical techniques such as SEM, XRD, ATR–FTIR and Raman spectroscopy. Finally, the use of described method for chitin isolation combined with biomineralization ex vivo resulted in the formation of crystalline (calcite) calcium carbonate-based deposits on the surface of chitinous scaffolds, which could serve as promising biomaterials for the wide range of biomedical, environmental and biomimetic applications.

Three-dimensional chitinous scaffolds often used in regenerative medicine, tissue engineering, biomimetics and technology are mostly isolated from marine organisms, such as marine sponges (Porifera). In this work, we report the results of the electrochemical isolation of the ready to use chitinous matrices from three species of verongiid demosponges (Aplysina archeri, Ianthella basta and Suberea clavata) as a perfect example of possible morphological and chemical dimorphism in the case of the marine chitin sources. The electrolysis of concentrated Na₂SO₄ aqueous solution showed its superiority over the chemical chitin isolation method in terms of the treatment time reduction: only 5.5 h for A. archeri, 16.5 h for I. basta and 20 h for the S. clavata sample. Further investigation of the isolated scaffolds by digital microscopy and SEM showed that the electrolysis-supported isolation process obtains chitinous scaffolds with well-preserved spatial structure and it can be competitive to other alternative chitin isolation techniques that use external accelerating factors such as microwave irradiation or atmospheric plasma. Moreover, the infrared spectroscopy (ATR-FTIR) proved that with the applied electrochemical conditions, the transformation into chitosan does not take place.