Chitosan hydrogel formation using laccase activated phenolics as cross-linkers

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Green Chemistry

Background:

• Chitosan hydrogels are promising for biomedical applications due to their biocompatibility.
• Traditional chemical cross-linkers pose toxicity risks.
• There is a need for safer, environmentally friendly cross-linking methods.

Purpose of the Study:

• To investigate the potential of laccase-oxidized phenolics as cross-linking agents for chitosan.
• To develop a novel green approach for synthesizing chitosan hydrogels.
• To evaluate the properties of these novel hydrogels.

Main Methods:

• Chitosan was cross-linked using laccase-oxidized phenolics (catechol, sinapic acid, caffeic acid, pyrogallol, eugenol).
• High-Performance Liquid Chromatography-Time of Flight-Mass Spectrometry (HPLC-TOF-MS) and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) were used for chemical characterization.
• Swelling properties and methylene blue release were assessed.
• Biocompatibility was evaluated using HEK293 cell line.

Main Results:

• Phenolics were successfully bonded to chitosan via laccase oxidation.
• Required phenolic concentrations for hydrogel formation ranged from 500μM (catechol) to 5000μM (sinapic acid).
• Laccase-oxidized caffeic acid and pyrogallol-chitosan hydrogels exhibited high water uptake (208.7% swelling for caffeic acid).
• No significant inhibition of HEK293 cell growth was observed with catechol or eugenol.

Conclusions:

• Laccase-oxidized phenolics are effective cross-linking agents for chitosan.
• This method presents a novel and green approach to synthesizing chitosan hydrogels.
• The resulting hydrogels show promising swelling and biocompatibility for potential biomedical applications.