Bacterial Cellulose-Chitosan Paper with Antimicrobial and Antioxidant Activities

Area of Science:

• Materials Science
• Biotechnology
• Polymer Science

Background:

• Bacterial cellulose (BC) is a versatile biomaterial with excellent mechanical properties.
• Chitosan (Ch) possesses inherent antimicrobial and antioxidant activities.
• Combining BC and Chitosan into nanocomposites can yield materials with synergistic functionalities.

Purpose of the Study:

• To develop and characterize paper-based bacterial cellulose-chitosan (BC-Ch) nanocomposites using two distinct fabrication methods.
• To evaluate the physical, antimicrobial, antioxidant, and antibiofilm properties of the resulting BC-Ch nanocomposites.
• To assess the retention of chitosan within the BC matrix.

Main Methods:

• Two methods were employed: immersion of pre-formed BC sheets in chitosan solution (BC-ChI) and impregnation of BC pulp with chitosan before sheet formation (BC-ChM).
• Characterization included assessment of physical properties (hydrophobicity, air barrier, crystallinity), surface morphology (fiber network, pore size), and chitosan leaching.
• Antimicrobial, antioxidant, and antibiofilm assays were conducted against specific bacterial and yeast strains.

Main Results:

• Both BC-ChI and BC-ChM retained the hydrophobic and air barrier properties of BC paper, along with high crystallinity.
• BC-ChI exhibited a denser fiber network and smaller pores compared to BC-ChM.
• Chitosan leaching was minimal (5% after 96h), indicating good retention.
• BC-Ch nanocomposites demonstrated significant antimicrobial activity against *Staphylococcus aureus*, *Pseudomonas aeruginosa*, and *Candida albicans*, and inhibited biofilm formation.
• Antioxidant activity was enhanced by chitosan incorporation.

Conclusions:

• Paper-based BC-Ch nanocomposites successfully integrate the beneficial properties of both bacterial cellulose and chitosan.
• The fabrication method influences the nanostructure of the nanocomposite.
• These BC-Ch nanocomposites exhibit promising antimicrobial, antibiofilm, and antioxidant functionalities, suitable for various applications.