Customizing porosity and mechanical strength in chitosan-based scaffolds for enhanced bone tissue regeneration

Chitosan is increasingly employed in bone tissue engineering due to its biocompatibility, biodegradability, and chemical versatility. This study focuses on the design and optimization of chitosan-based scaffolds, emphasizing the influence of key preparation parameters on their structural and mechanical performance. Formulations were prepared using chitosan concentrations from 1.0 % to 2.5 % (w/v), freezing temperatures of -20 °C and -196 °C, genipin crosslinker from 1.5 % to 10 % (w/v), and magnetite nanoparticle addition at 10 % and 20 % (w/w relative to chitosan). For CS solution frozen at -20 °C, the increase of CS concentration, genipin crosslinking (10 %), and incorporation of magnetite nanoparticles resulted in enhanced compressive strength and modulus of scaffolds, reaching values of 0.40 MPa and 3.57 MPa, respectively. This scaffold offers a combination of porosity (above 80 %) and mechanical strength suitable for trabecular bone regeneration. Freezing the CS solution at -196 °C also enhanced the compressive strength and modulus (0.25 MPa and 1.6 MPa, respectively, versus 0.13 MPa and 1.2 MPa at -20 °C), while resulting in lower porosity (31 %), making it suitable for applications where higher mechanical integrity is required. These findings underscore the tunability of chitosan scaffolds through parameter control, offering a robust approach for developing chitosan-based biomaterials tailored to distinct bone tissue environments.