Copper-zinc/chitosan complex hydrogels: Rheological, degradation and biological properties.

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Polymer hydrogels crosslinked by therapeutic metal ions are gaining interest for biomedical uses.
• Chitosan hydrogels are extensively studied for tissue engineering and drug delivery.
• Copper and zinc ions play crucial roles in bone regeneration.

Purpose of the Study:

• To investigate the physicochemical and biological properties of bimetallic-chitosan complex hydrogels.
• To explore the impact of varying cupric (Cu²⁺) and zinc (Zn²⁺) ion content on hydrogel characteristics.
• To assess the potential of these hydrogels for bone regeneration applications.

Main Methods:

• Fabrication of bimetallic-chitosan hydrogels with different Cu²⁺ and Zn²⁺ concentrations.
• Characterization using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS).
• Evaluation of physical properties (swelling, shear modulus), in vitro degradation, and cytotoxicity (MTT assay).

Main Results:

• SEM revealed distinct morphological changes based on metal ion content.
• FTIR and XRD confirmed the formation of bimetallic-chitosan aerogels with strong physical crosslinking.
• Hydrogels exhibited decreased swelling, increased shear modulus with higher Cu²⁺ content, negligible ion release, good stability, and tunable cytotoxicity.

Conclusions:

• Cu²⁺ and Zn²⁺ ions effectively act as physical crosslinkers in chitosan hydrogels.
• The developed bimetallic-chitosan hydrogels demonstrate promising physicochemical and biological properties for bone regeneration.
• Density Functional Theory (DFT) predictions support stronger chitosan-Cu interactions compared to chitosan-Zn interactions.