Preparation of natural chitosan from shrimp shell with different deacetylation degree.

The main aim of the present study was to produce natural chitosan with different deacetylation degree from shrimp shells. Three deacetylation degrees of chitosan were obtained through boiling the chitin in NaOH (50% (w/v)) at 110 °C for 4 h. The samples were labelled as NCS1, NCS2 and NCS3 according to the number of times they were treated with alkaline solution. The functional groups of the obtained products and the degree of deacetylation were determined through Fourier transformed infra-red spectroscopy. Scanning electron microscope was employed to characterise the morphology of the produced materials. Cell viability assay was carried out using mesenchymal stem cells cultured on the samples for 7 days. The results showed that the deacetylation degree of chitin, NCS1, NCS2 and NCS3 became 50.1, 73.5, 82.3 and 82.5%, respectively. The natural chitin had carnation-like morphology. NCS1, NCS2 and NCS3 had the raised hills with the smaller and denser Gulbergs, however, there was no significant difference between NCS2 and NCS3 regarding the structure and deacetylation degree. Moreover, the result of the cell culture experiment indicated that the number of cells on the NCS1 was less than that of the NCS2 after 7 days. [ABSTRACT FROM AUTHOR]