Functionalization of an alginate-based material by oxidation and reductive amination

• Autores: Huamani-Palomino R.G., Córdova B.M., Elvis Renzo Pichilingue L., Venâncio T., Valderrama A.C.
• Formato: artículo
• Fecha de Publicación: 2021
• Institución: Consejo Nacional de Ciencia Tecnología e Innovación
• Repositorio: CONCYTEC-Institucional
• Lenguaje: inglés
• OAI Identifier: oai:repositorio.concytec.gob.pe:20.500.12390/2409
• Enlace del recurso: https://hdl.handle.net/20.500.12390/2409; https://doi.org/10.3390/polym13020255
• Nivel de acceso: acceso abierto
• Materia: Reductive amination; Alginate; Functionalization; Oxidation; http://purl.org/pe-repo/ocde/ford#1.04.01

This research focused on the synthesis of a functional alginate-based material via chemical modification processes with two steps: oxidation and reductive amination. In previous alginate functionalization with a target molecule such as cysteine, the starting material was purified and characterized by UV-Vis,1 H-NMR and HSQC. Additionally, the application of FT-IR techniques during each step of alginate functionalization was very useful, since new bands and spiked signals around the pyranose ring (1200–1000 cm−1) and anomeric region (1000–750 cm−1) region were identified by a second derivative. Additionally, the presence of C1-H1 of β-D-mannuronic acid residue as well as C1-H1 of α-L-guluronic acid residue was observed in the FT-IR spectra, including a band at 858 cm−1 with characteristics of the N-H moiety from cysteine. The possibility of attaching cysteine molecules to an alginate backbone by oxidation and post-reductive amination processes was confirmed through13 C-NMR in solid state; a new peak at 99.2 ppm was observed, owing to a hemiacetal group formed in oxidation alginate. Further, the peak at 31.2 ppm demonstrates the presence of carbon-CH2-SH in functionalized alginate—clear evidence that cysteine was successfully attached to the alginate backbone, with 185 µmol of thiol groups per gram polymer estimated in alginate-based material by UV-Visible. Finally, it was observed that guluronic acid residue of alginate are preferentially more affected than mannuronic acid residue in the functionalization. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.