Highly Elastic and Tough Interpenetrating Polymer Network-Structured Hybrid Hydrogels for Cyclic Mechanical Loading-Enhanced Tissue Engineering

Although
hydrogels are extensively investigated as biomaterials
due to their ability to mimic cellular microenvironments, they are
often limited by their poor physical properties in response to mechanical
loads, including weak gel strength, brittleness, and permanent deformation.
Recently, interpenetrating polymer network (IPN) hydrogels have gained
substantial attention for their use in investigating changes in encapsulated
cell behaviors under mechanical stimulation. However, despite recent
success in developing highly elastic IPN-structured hydrogels, it
remains a great technical challenge to endow them with biocompatibility
and biodegradability due to use of toxic chemicals, nonbiodegradable
prepolymers, and harsh reaction conditions. In this study, we report
on the synthesis and formation of highly elastic and tough IPN-structured
hydrogels based on alginate and gelatin, which are biocompatible and
biodegradable. Mechanical stimulation enhanced the proliferation and
osteogenic differentiation of encapsulated human mesenchymal stem
cells in the IPN-structured hydrogels. These new biocompatible, biodegradable,
and tough elastomeric hydrogels provide an exciting platform for studying
stem cell behaviors such as proliferation and differentiation under
mechanical stimulation and may broaden the applications of hydrogels
in the fields of tissue engineering and regenerative medicine.