A novel composite construct increases the vascularization potential of PEG hydrogels through the incorporation of large fibrin ribbons.

Developing a mechanism to vascularize tissue-engineered constructs is imperative for transplant function and integration, particularly when delivering hypoxia-sensitive tissues, such as pancreatic islets. Previous efforts have focused on bulk modifications of scaffold materials rendering the entire construct permissive to vessel penetration or the formation of a porous structure where vessels can infiltrate the empty spaces. Here, we describe a novel construct composed of large fibrin ribbons encapsulated within a poly(ethylene glycol) (PEG) hydrogel.

Inhibition of gamma-secretase activity promotes differentiation of embryonic pancreatic precursor cells into functional islet-like clusters in poly(ethylene glycol) hydrogel culture.

We assessed the ability of a gamma-secretase inhibitor to promote the in vitro differentiation of induced embryonic pancreatic precursor cell aggregates into functional islet-like clusters when encapsulated within a three-dimensional hydrogel. Undifferentiated pancreatic precursor cells were isolated from E.15 rat embryos, dissociated into single cells, and aggregated in suspension-rotation culture.

Entrapped collagen type 1 promotes differentiation of embryonic pancreatic precursor cells into glucose-responsive beta-cells when cultured in three-dimensional PEG hydrogels.

Development of an alternative source of functional, transplantable beta-cells to replace or supplement cadaveric tissue is critical to the future success of islet cell transplantation therapy. Embryonic pancreatic precursor cells are desirable as a renewable source of beta-cells as they are both proliferative and inherently capable of pancreatic cell differentiation. We have previously shown that precursor cells undergo selective beta-cell differentiation when dissociated and photoencapsulated in a polyethylene glycol (PEG) hydrogel network; however, these cells remained immature and were not glucose responsive.

Selective beta-cell differentiation of dissociated embryonic pancreatic precursor cells cultured in synthetic polyethylene glycol hydrogels.

Continuing advances in islet cell transplantation have been promising; however, several limitations, including severe shortage of transplantable islets, hinder the widespread use of this therapy. Pancreatic precursor cells are one alternative to cadaveric donor islets. These cells found in the developing pancreatic buds are capable of self-renewal and also have the innate ability to become insulin-producing beta-cells.

Delivery of osteoinductive growth factors from degradable PEG hydrogels influences osteoblast differentiation and mineralization.

Degradable poly(ethylene glycol) (PEG) hydrogels with varying mass loss profiles were investigated to assess their applicability as delivery vehicles for osteoinductive growth factors in bone tissue engineering. Protein release is readily controlled by changes in both the structure (i.e.