Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Oct 13;10(10):655.
doi: 10.3390/gels10100655.

Tuning Antioxidant Function through Dynamic Design of Chitosan-Based Hydrogels

Manuela Maria Iftime  1 , Gabriela Liliana Ailiesei  1 , Daniela Ailincai  1   2
Affiliations

Tuning Antioxidant Function through Dynamic Design of Chitosan-Based Hydrogels

Manuela Maria Iftime et al. Gels. .

Abstract

Dynamic chitosan-based hydrogels with enhanced antioxidant activity were synthesized through the formation of reversible imine linkages with 5-methoxy-salicylaldehyde. These hydrogels exhibited a porous structure and swelling capacity, influenced by the crosslinking degree, as confirmed by SEM and POM analysis. The dynamic nature of the imine bonds was characterized through NMR, swelling studies in various media, and aldehyde release measurements. The hydrogels demonstrated significantly improved antioxidant activity compared to unmodified chitosan, as evaluated by the DPPH method. This research highlights the potential of developing pH-responsive chitosan-based hydrogels for a wide range of biomedical applications.

Keywords: antioxidant properties; chitosan; dynamic behavior; hydrogels; imine.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Scheme 1
Scheme 1
(a) Chitosan imination reaction with 5-methoxysalicylaldehyde; (b) Overview of hydrogel composition, gelation time, and inverted tube test images.
Scheme 2
Scheme 2
Schematic representation of hydrogel formation (Sx) and their dynamic properties attributed to reversible imine units.
Figure 1
Figure 1
The FTIR spectra of the xerogels (S1, S3 and S6), chitosan, and 5-methoxysalicylaldehyde (A).
Figure 2
Figure 2
(a) 1H-NMR spectra of the hydrogel (S3) over time; (b) 1H-NMR spectra of the studied hydrogels after 7 days.
Scheme 3
Scheme 3
Schematic representation of pH–responsiveness of the hydrogels under different pH conditions.
Figure 3
Figure 3
1H NMR spectra of representative hydrogels (S1 and S3) obtained under different pH conditions over time: (a) acidic pH and (b) basic pH.
Figure 3
Figure 3
1H NMR spectra of representative hydrogels (S1 and S3) obtained under different pH conditions over time: (a) acidic pH and (b) basic pH.
Figure 4
Figure 4
SEM micrographs of S1, S3, and S6 hydrogels.
Figure 5
Figure 5
(a) Mass equilibrium swelling (MES) of hydrogels as a function of pH and representative images of hydrogels after swelling in different media; (b) cumulative aldehyde release from xerogels in different media (*: p < 0.05; **: p < 0.01; ***: p < 0.03; ****: p < 0.0001); (c) hydrolytic stability of xerogels in different media (***: p < 0.03; ****: p < 0.0001); (d) gel fraction of the understudy xerogels (Sx).
Figure 6
Figure 6
Cumulative aldehyde release from xerogels in different media over time; (a) H2O; (b) PBS (pH = 7.4); (c) acetate buffer (pH = 5.5).
Figure 7
Figure 7
Antioxidant activity of hydrogels: (a) Sx and (b) S’x and their references; visual representation of the colorimetric changes in hydrogel solutions at different concentrations following exposure to DPPH: (c) S1 and (d) S’1.
Figure 8
Figure 8
The scavenging activity of the hydrogels: (a) S1, S’1, aldehyde (A1), chitosan, and ascorbic acid; (b) S3, S’3, aldehyde (A3), chitosan, and ascorbic acid; (c) S6, S’6, aldehyde (A6), chitosan, and ascorbic acid.
Figure 9
Figure 9
1H-NMR spectra of hydrogel S3 after exposure to different amounts of DPPH.
See this image and copyright information in PMC

References

    1. Bhattacharyya A., Chattopadhyay R., Mitra S., Crowe S.E. Oxidative Stress: An Essential Factor in the Pathogenesis of Gastrointestinal Mucosal Diseases. Physiol. Rev. 2014;94:329–354. doi: 10.1152/physrev.00040.2012. - DOI - PMC - PubMed
    1. Abd El-Ghany N.A., Abdel Aziz M.S., Abdel-Aziz M.M., Mahmoud Z.M. Reinforcement of antimicrobial activity and swelling ability of starch-g-poly 4-acrylamidobenzoic acid using chitosan nanoparticles. Cellul. Chem. Technol. 2023;57:803–813. doi: 10.35812/CelluloseChemTechnol.2023.57.71. - DOI
    1. Khalil I., Yehye W.A., Etxeberria A.E., Alhadi A.A., Dezfooli S.M., Julkapli N.B.M., Basirun W.J., Seyfoddin A. Nanoantioxidants: Recent Trends in Antioxidant Delivery Applications. Antioxidants. 2019;9:24. doi: 10.3390/antiox9010024. - DOI - PMC - PubMed
    1. Sezgin-Bayindir Z., Losada-Barreiro S., Fernández-Bravo S., Bravo-Díaz C. Innovative Delivery and Release Systems for Antioxidants and Other Active Substances in the Treatment of Cancer. Pharmaceuticals. 2023;16:1038. doi: 10.3390/ph16071038. - DOI - PMC - PubMed
    1. Li M., Mu Y., Xu Q., Jin L., Fu Y. Injectable, Rapid Self-Healing, Antioxidant and Antibacterial Nanocellulose-Tannin Hydrogels Formed via Metal-Ligand Coordination for Drug Delivery and Wound Dressing. Ind. Crop. Prod. 2024;208:117876. doi: 10.1016/j.indcrop.2023.117876. - DOI

LinkOut - more resources