Alkali Treated 3D Chitosan Scaffolds with Enhanced Strength and Stability

3D chitosan scaffolds treated with alkali showed enhanced mechanical properties and stability in aqueous conditions. Chitosan is a preferred polymer for biomedical applications due to its antimicrobial, antioxidant and wound healing properties. Chitosan has been made into films, fibers, micro and nanoparticles and electrospun membranes for tissue engineering, drug delivery and other medical applications. However, materials made from chitosan have poor strength and stability. Compared to other forms, 3D scaffolds are more suitable for tissue engineering and other applications but are relatively easily susceptible to moisture and have poor strength due to their porous structure. Several physical and chemical approaches have been used to increase the strength and stability of chitosan biomaterials. In this study, we demonstrate that a simple treatment with alkali will substantially improve the strength and stability of freeze-dried 3D chitosan scaffolds. Three different concentrations of chitosan were lyophilized and made into scaffolds with varying properties. These scaffolds were alkali treated and tested for their increase in strength, resistance to water and other properties. Up to 50% increase in strength was possible when higher concentrations of chitosan and alkali treatment were used. The scaffolds have good activity against both gram positive and gram negative bacteria with the highest percentage of inhibition being 97%. Scaffolds also showed the ability to generate hydroxyapatite when incubated in phosphate buffered saline (PBS) for 7 days. This study provides a novel approach to obtain 3D chitosan scaffolds with properties suitable for medical, food and other applications.