Visible-light crosslinked caffeic acid–modified gelatin hydrogels with tunable mechanical, adhesive, and antioxidant properties
Journal
International Journal of Biological Macromolecules
Journal Volume
338
Start Page
149665
ISSN
01418130
Date Issued
2026-01
Author(s)
Abstract
Gelatin–catechol hydrogels possess significant potential for bioadhesive and antioxidant applications, but their practical use is hindered by weak mechanical strength, unstable network formation, and uncontrolled catechol oxidation. Conventional UV-mediated crosslinking further introduces phototoxicity concerns and reduced polymerization efficiency due to catechol radical scavenging, highlighting the need for safer and more effective visible-light-based strategies. In this study, we synthesized gelatin-based hydrogels functionalized with caffeic acid (CA-2OH) via N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling. These hydrogels were subsequently crosslinked either under UV light using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) or under visible light using Eosin Y (EY), triethanolamine (TEOA), and N-vinylcaprolactam (VC), hereafter referred to as EYTV. CA-2OH conjugation was verified by UV–Visible spectroscopy, 1H NMR, and quantitative assays. Visible-light crosslinking, particularly EYTV, produced hydrogels with enhanced mechanical properties, network stability, and fatigue resistance. EYTV hydrogels reached a compressive Young's modulus of 4.82 ± 0.28 kPa, compared with 2.83 ± 0.11 kPa in EY and 5.47 ± 1.02 kPa in LAP. Rheological analysis confirmed shear-thinning behavior, injectability, and partial self-healing. EYTV also significantly improved tissue adhesion (18.33 ± 0.42 kPa), representing a 192 % increase relative to EY and a 33 % increase compared with LAP, and yielded compact pore morphology, reduced swelling, and enhanced enzymatic stability. Antioxidant assays showed higher radical-scavenging activity in EY hydrogels (74.35 ± 1.48 %) owing to unreacted catechols, while LAP and EYTV exhibited reduced activity (29.71 ± 2.32 % and 15.58 ± 2.86 %). Overall, GelCA-2OH hydrogels provide tunable mechanics, strong adhesion, and robust cytocompatibility, making them promising for tissue engineering and oxidative stress mitigation.
Subjects
Caffeic acid
Catechol
Gelatin
Hydrogel
Photocrosslinking
Visible-light crosslinked hydrogel
Publisher
Elsevier B.V.
Type
journal article