Optimization of Injectable Thermosensitive Scaffolds with Enhanced Mechanical Properties for Cell Therapy

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Chitosan hydrogels are promising for biomedical applications.
• Developing injectable, thermosensitive chitosan hydrogels without chemical modification is desirable.
• Optimizing formulation for mechanical properties and cell compatibility is crucial.

Purpose of the Study:

• To investigate the impact of gelling agent concentration on chitosan hydrogel properties.
• To develop optimized chitosan hydrogels for cell therapy and tissue engineering.
• To evaluate cell encapsulation efficiency and long-term cell viability within the new hydrogels.

Main Methods:

• Formulation of chitosan hydrogels using sodium hydrogen carbonate with beta-glycerophosphate (BGP) or phosphate buffer (PB).
• Characterization of mechanical properties (Young's modulus), gelation kinetics, osmolality, and swelling behavior.
• Assessment of cell encapsulation, distribution, viability, and growth (L929 mouse fibroblasts and human mesenchymal stem cells).

Main Results:

• New formulations exhibit up to a 50-fold increase in Young's modulus compared to conventional chitosan-BGP hydrogels.
• Achieved iso-osmolality while maintaining injectable properties.
• Increased PB concentration accelerated gelation but decreased mechanical properties; BGP had a lesser effect.
• Encapsulated L929 fibroblasts showed enhanced viability and growth.
• Human mesenchymal stem cells maintained viability and metabolic activity for 7 days in vitro.

Conclusions:

• Injectable chitosan thermosensitive hydrogels can be formed without chemical modification.
• Optimized formulations demonstrate superior mechanical strength and biocompatibility.
• These hydrogels show significant potential for cell therapy and tissue engineering applications.