Engineering complex tissue-like microenvironments with biomaterials and biofabrication.

Advances in tissue engineering for both system modeling and organ regeneration depend on embracing and recapitulating the target tissue's functional and structural complexity. Microenvironmental features such as anisotropy, heterogeneity, and other biochemical and mechanical spatiotemporal cues are essential in regulating tissue development and function. Novel biofabrication strategies and innovative biomaterial design have emerged as promising tools to better reproduce such features.

Optimizing the physical properties of collagen/hyaluronan hydrogels by inhibition of polyionic complexes formation at pH close to the collagen isoelectric point.

Collagen/hyaluronan hydrogels with physical properties well suited for biomedical applications are challenging to synthesize due to the formation of polyionic complexes (PICs). A systematic physicochemical study was thus performed to determine novel conditions to inhibit the formation of collagen/hyaluronan PICs and obtain composite hydrogels with high physical properties. Using a range of pH from 1 to 5.

Combining biomimetic collagen/hyaluronan hydrogels with discogenic growth factors promotes mesenchymal stroma cell differentiation into Nucleus Pulposus like cells.

Based on stem cell injection into degenerated Nucleus Pulposus (NP), novel treatments for intervertebral disc (IVD) regeneration were disappointing because of cell leakage or inappropriate cell differentiation. In this study, we hypothesized that mesenchymal stromal cells encapsulated within injectable hydrogels possessing adequate physico-chemical properties would differentiate into NP like cells. Composite hydrogels consisting of type I collagen and tyramine-substituted hyaluronic acid (THA) were prepared to mimic the NP physico-chemical properties.