Multifunctional Polysaccharide Hydrogels Capable of Mineralization, Vascularization, and Anti-bacterial Efficacy

The use of hydrogels in bone regeneration research has shown to provide a variety of benefits. Hydrogels can be modified to optimize their rheological and mechanical properties for improved bone formation and vascularization at defect sites. Hydrogels are a type of hydrated polymeric materials with properties similar to those of natural tissue as a result of their ample water constituents. The hydrogels used in this study were modified derivatives of methylcellulose, agarose, and chitosan blends capable of rapid transition from sols to gels [Zuidema 2011]. A natural chemical compound, genipin, was added to induce cross-linking in the chitosan component of the hydrogels. The added control of cross-linking enabled the increased manipulation of hydrogel stiffness without alterations in polysaccharide constituents. The ability to create multiple hydrogels with varying stiffness allowed for the determination of an optimal hydrogel stiffness for the support of mineralization and vascularization in bone defects. Hydrogel stiffness is an essential factor in cell adhesion and function, with low-stiffness gels favoring vascularization and high-stiffness gels favoring mineralization. This study aimed to determine an optimal gel stiffness that could promote both mineralization and vascularization to encourage the formation of healthy mineralized bone in defect sites. In addition, the inherent anti-bacterial efficacy of the hydrogels was evaluated as it pertained to the issue of sterilization in bone defects. In this study, we designed multifunctional hydrogels with varied stiffness and assessed their anti-bacterial efficacy and ability to promote mineralization and vascularization for eventual use in bone defect healing.