Chitosan Hydrogels Crosslinked with Oxidized Sucrose for Antimicrobial Applications

Area of Science:

• Materials Science
• Biochemistry
• Polymer Chemistry

Background:

• Oxidized sucrose (OS) reacts with chitosan to form carbohydrate-only hydrogels.
• Initial hydrogels contain unstable imine bonds and unreacted aldehydes, limiting biomaterial applications.
• Need for stable, carbohydrate-based biomaterials with antimicrobial properties.

Purpose of the Study:

• To stabilize chitosan-oxidized sucrose hydrogels (CTSGs) by reducing imine bonds and aldehydes.
• To characterize the structure and properties of the reduced CTSGs.
• To evaluate the antimicrobial efficacy and potential of CTSGs as biomaterials.

Main Methods:

• Chitosan hydrogels (CTSGs) were synthesized via crosslinking chitosan with oxidized sucrose.
• Sodium borohydride reduction was employed to stabilize the hydrogel structure.
• Fourier transform infrared and ¹³C nuclear magnetic resonance spectroscopies were used for characterization.
• Antimicrobial activity was tested against *Escherichia coli*.

Main Results:

• Reduction successfully converted imine bonds to secondary amines and aldehydes to alcohols.
• The degree of crosslinking (CR) was dependent on the oxidized sucrose feed amount.
• Increased CR enhanced thermal stability and dynamic moduli while decreasing swelling.
• CTSGs demonstrated concentration-dependent antimicrobial activity against *Escherichia coli*.

Conclusions:

• Reduced CTSGs offer improved structural stability compared to unreduced counterparts.
• The properties and antimicrobial performance of CTSGs can be tuned by controlling the crosslinking degree.
• These fully carbohydrate-based hydrogels show promise for medical, pharmaceutical, and food applications.