Maria H, Gopi S, Volova T, C. M. Fernandes S, Thomas S. Extraction of Nanochitin from Marine Resources and Fabrication of Polymer Nanocomposites: Recent Advances

Industrial sea food residues, mainly crab and shrimp shells, are considered to be the most promising and abundant source of chitin. In-depth understanding of the biological properties of chitin and scientific advancements in the field of nanotechnology have enabled the development of high-performance chitin nanomaterials. Nanoscale chitin is of great economic value as an efficient functional and reinforcement material for a wide range of applications ranging from water purification to tissue engineering. The use of polymers and nanochitin to produce (bio) nanocomposites offers a good opportunity to prepare bioplastic materials with enhanced functional and structural properties. Most processes for nanochitin isolation rely on the use of chemical, physical or mechanical methods. Chitin-based nanocomposites are fabricated by various methods, involving electrospinning, freeze drying, etc. This review discusses the progress and new developments in the isolation and physico-chemical characterization of chitin; it also highlights the processing of nanochitin in various composite and functional materials.

Comparison of physicochemical and rheology properties of Shiitake stipes-derived chitin nanocrystals and nanofibers

Chitin production from fungal sources has gained increased attention in recent years in terms of continuous supply and safety. In this study, we produced chitin from Shiitake stipes through deproteinization, depigmentation, demineralization and removal of glucans, and then prepared chitin nanocrystal (ChNC) and chitin nanofibers (ChNF) by acid hydrolysis or high-pressure homogenizers. Such obtained ChNFs have higher length than the ChNCs with a length of 142.4 ± 40.4 nm, with the similar diameter (9 nm). In addition, the purity of ChNC and ChNF were over 98 % measured by HPAEC. The zeta potential analysis showed that ChNC is stable in acid form, while ChNF is in the opposite. Finally, we evaluated the rheology properties of samples to find the impact of salt concentrations on nanoparticles interactions. Overall, the fungi-derived chitin nanomaterials with diversity of characters exhibit immense potential for applications in nutraceutical and food industry.

Construction of blood compatible chitin/graphene oxide composite aerogel beads for the adsorption of bilirubin

Excess bilirubin in blood can provoke hepatic damage and related malfunctions. Hereby we designed and constructed a novel bilirubin adsorbent, called chitin/graphene oxide (Ch/GO) composite aerogel beads, for efficient, fast and safe removal for bilirubin. The Ch/GO aerogel beads were prepared from chitin and GO in a NaOH/urea aqueous solution, followed dried by supercritical carbon dioxide. The morphology, structure and properties of the Ch/GO composite aerogel beads were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and compressive strength measurement. The results indicated that GO was successfully bound to chitin matrix with enhanced surface area, thermal stability and mechanical strength. The adsorption capacity of Ch/GO composite aerogel beads for bilirubin was examined by UV-vis spectrophotometry. Moreover, batch adsorption results revealed that the Ch/GO composite aerogel beads showed excellent bilirubin adsorption capacity (484.1 ± 16.9 mg/g) and short adsorption equilibrium time (0.5 h) under optimized condition. Furthermore, the Ch/GO aerogel beads exhibited a lower hemolysis property and improved anticoagulant property. Hence, this work provided a new strategy to develop a novel blood compatible bilirubin adsorbent, which presented good application potential for bilirubin adsorption.

Comparison of nanocrystals and nanofibers produced from shrimp shell α-chitin: From energy production to material cytotoxicity and Pickering emulsion properties

Chitin nanocrystals (ChNCs) and chitin nanofibers (ChNFs) are nanomaterials with great innovative potential for sustainable applications in academic and industrial fields. The research related to their isolation and production, characterization, and utilization is still new. The aim of this study is to investigate the effects of the production process on the morphology and properties of ChNFs and ChNCs produced from the same source of chitin. ChNCs were prepared by acid hydrolysis of commercial shrimp shell α-chitin, and ChNFs were prepared by mechanical defibrillation using closed loop supermass colloidal grinding. Differences in their shape, size, and crystallinity were observed. ChNFs were observed to have higher aspect ratio, higher viscosity, and better thermal stability than ChNCs. Although the ChNC casting film had a higher degree of transparency, it had lower mechanical properties than ChNF film. In addition, the capacities of each nanomaterial for producing Pickering emulsions were comparatively investigated. ChNFs showed better oil-in-water emulsion stabilization ability than ChNCs at the same concentrations. In vitro cytotoxicity assays using two epithelial-like cell lines and two fibroblast-like cell lines demonstrated that both nanomaterials were non-toxic. Finally, we evaluated the economics of production using process engineering simulation to assess the energy and chemical consumption for each process of production of these nanomaterials.