Bimolecular based heparin and self-assembling hydrogel for tissue engineering applications

One major goal of tissue engineering is to develop new biomaterials that are similar structurally and functionally to the extracellular matrix (ECM) to mimic natural cell environments. Recently, different types of biomaterials have been developed for tissue engineering applications. Among them, self-assembling peptides are attractive candidates to create artificial cellular niches, because their nanoscale network and biomechanical properties are similar to those of the natural ECM. Here, we describe the development of a new biomaterial for tissue engineering composed by a simple combination of the self-assembling peptide RAD16-I and heparin sodium salt. As a consequence of the presence of heparin moieties the material acquired enhances the capacity of specific binding and release of growth factors (GFs) with heparin binding affinity such as VEGF165. Promising results were obtained in the vascular tissue engineering area, where the new composite material supported the development of tubular-like structures within a three dimensional (3D) culture model. Moreover, the new scaffold enhances the cell survival and chondrogenic commitment of adipose-derived stem cells (ADSC). Interestingly, the expression of specific markers of mature cartilage tissue including collagen type II was confirmed by western blot and real-time PCR. Furthermore, positive staining for proteoglycans (PGs) indicated the synthesis of cartilage tissue ECM components. Finally, the constructs did not mineralize and exhibited mechanical properties of a tissue undergoing chondrogenesis. Altogether, these results suggest that the new composite is a promising "easy to prepare" material for different reparative and regenerative applications.