Mechanically robust and bioadhesive collagen and photocrosslinkable hyaluronic acid semi-interpenetrating networks.

In this work, we present a class of hydrogels that leverage the favorable properties of the photo-cross-linkable hyaluronic acid (HA) and semi-interpenetrating collagen components. The mechanical properties of the semi-interpenetrating-network (semi-IPN) hydrogels far surpass those achievable with collagen gels or collagen gel-based semi-IPNs. Furthermore, the inclusion of the semi-interpenetrating collagen chains provides a synergistic mechanical improvement over unmodified HA hydrogels. Collagen-HA semi-IPNs supported fibroblast adhesion and proliferation and were shown to be suitable for cell encapsulation at high levels of cell viability. To demonstrate the utility of the semi-IPNs as a microscale tissue engineering material, cell-laden microstructures and microchannels were fabricated using soft lithographic techniques. Given their enhanced mechanical and biomimetic properties, we anticipate that these materials will be of value in tissue engineering and three-dimensional cell culture applications.