Characterization of Lyophilized Crosslinked Chitosan Scaffold for Tissue Engineering and its Potential for Vascularization

Abstract

The rapid advancement in biomaterial research and three-dimensional (3D) printing technology in the field of tissue engineering has opened the door for major breakthroughs in biomedical research. These include restoration of 3D anatomic defects, reconstruction of organs, and development of scaffolds to regenerate and heal bone defects, lost cartilage, and chronic wound sites. The biopolymer chitosan has been shown in several studies to be a promising scaffold material for bone, cartilage, and wound healing because of its biocompatibility, biodegradation, mechanical properties, high porosity and ease of processing. This work aimed to expand our understanding of chitosan as a scaffold by focusing on the relationship between the crosslinking density of freeze-dried (lyophilized) chitosan scaffolds and scaffold pore size and geometry, Young’s modulus, biodegradation kinetics, biocompatibility, and elution kinetics in relation to drug delivery applications. The results here suggest that higher concentrations of the crosslinking reagent, glutaraldehyde (GA), correlated with a higher Young’s modulus, smaller and more uniform pores, higher cell proliferation, slower degradation rates, and higher rates of elution of solution from the scaffold. Additionally, this work attempted to develop a technique for 3D printing an embedded vascular network within a bulk chitosan scaffold using a 3D-printed sacrificial Laponite gel structure, casting the structure within crosslinked chitosan, and then evacuating it from the bulk scaffold post lyophilization. The development of this technique was unsuccessful due to the inability to achieve high resolution prints of vascular networks within the lyophilized chitosan scaffold. However, this technique showed potential and warrants further research. In all, the manipulation of lyophilized chitosan produced various attributes that show its promise as a scaffold for tissue engineering.