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- Nokling-Eide, Katharina, et al.
(författare)
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Acid preservation of cultivated brown algae Saccharina latissima and Alaria esculenta and characterization of extracted alginate and cellulose
- 2023
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 71, s. 103057-
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Tidskriftsartikel (refereegranskat)abstract
- Cultivated brown algae represent an important potential source of carbohydrate polymers for packaging and other biobased materials. However, their exploitation is currently limited by a short harvest season and a lack of cost-effective and sustainable methods to preserve biopolymer quality. In the present study, cultivated Saccharina latissima (SL) and Alaria esculenta (AE) were preserved with formic acid at 4, 13 and 20 degrees C for up to 16 weeks prior to extraction and characterization of alginate and cellulose. The data show up to 40 % increased yield of alginate from preserved biomass compared with fresh and non-preserved biomass, primarily due to removal of minerals and other soluble compounds during the acid wash. Acid preservation and storage caused a reduction in alginate weight average molecular weight (Mw) that was mainly dependent on storage temperature and to a lesser extent on storage time; storage at 4 degrees C maintained the Mw of alginates at 350-500 kDa. Preservation had no effect on the guluronate block structure of the extracted alginates, but guluronic acid content and block length increased in the non-preserved samples, presumably due to enzymatic degradation of the alginate's M-rich re-gions. Preservation of the seaweed resulted in an increased cellulose yield compared with fresh and non -preserved biomass, again due to the biomass being reduced during acid wash. The molecular weight and crys-tallinity of cellulose were not altered by the process. Altogether our findings demonstrate that acid preservation at low temperatures can effectively stabilize seaweed biomass while preserving alginate and cellulose quality for biomaterials and other applications.
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| 2. |
- Sandvig, Ioanna, et al.
(författare)
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RGD-peptide modified alginate by a chemoenzymatic strategy for tissue engineering applications
- 2015
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 103:3, s. 896-906
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Tidskriftsartikel (refereegranskat)abstract
- One of the main challenges in tissue engineering and regenerative medicine is the ability to maintain optimal cell function and survival post-transplantation. Biomaterials such as alginates are commonly used for immunoisolation, while they may also provide structural support to the cell transplants by mimicking the extracellular matrix. In this study, arginine-glycine-aspartate (RGD)-peptide-coupled alginates of tailored composition were produced by adopting a unique chemoenzymatic strategy for substituting the nongelling mannuronic acid on the alginate. Alginates with and without RGD were produced with high and low content of G. Using carbodiimide chemistry 0.1-0.2% of the sugar units were substituted by peptide. Furthermore, the characterization by H-1-nuclear magnetic resonance (NMR) revealed by-products from the coupling reaction that partly could be removed by coal filtration. Olfactory ensheathing cells (OECs) and myoblasts were grown in two-dimensional (2D) and 3D cultures of RGD-peptide modified or unmodified alginates obtained by the chemoenzymatically strategy and compared to native alginate. Both OECs and myoblasts adhered to the RGD-peptide modified alginates in 2D cultures, forming bipolar protrusions. OEC encapsulation resulted in cell survival for up to 9 days, thus demonstrating the potential for short-term 3D culture. Myoblasts showed long-term survival in 3D cultures, that is, up to 41 days post encapsulation. The RGD modifications did not result in marked changes in cell viability in 3D cultures. We demonstrate herein a unique technique for tailoring peptide substituted alginates with a precise and flexible composition, conserving the gel forming properties relevant for the use of alginate in tissue engineering. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 896-906, 2015.
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