Heparin Improves Viability and Function of Encapsulated MIN6 Cells

摘要

Photopolymerisation is an accepted method for encapsulating cells for therapeutic applications. However certain cell types, such as pancreatic cells for diabetes therapies, may be sensitive to the photoinitators, ultraviolet (UV) light or the radicals generated by the process. In this research, the various elements of the photopolymerisation process were tested individually in a calcium complexed alginate gel. MIN6 insulinoma cells (10~6/mL) remained viable after exposure within the alginate to either UV light, photoinitiator or UV plus the initiator. However, the cell's metabolic activity was significantly reduced by exposure to UV light, and was reduced below detectable levels in the presence of UV plus initiator. Using a poly (vinyl alcohol) (PVA) hydrogel system, the metabolic activity was similarly undetectable when 10~6/mL were incorporated, although the cells again demonstrated high viability. Increasing cell numbers by an order of magnitude allowed detection of metabolic activity and showed that the cells remained metabolically active up to 15 days. Heparin was incorporated into the PVA gels in an attempt to reverse or minimize the damage caused by the radicals. While it is unclear the exact role that the addition of heparin plays, the cells remained metabolically active for significantly longer periods, and also started to form cell clusters. Thus, the addition of heparin or related extracellular matrix polysaccharides is an important consideration when attempting to photoencapsulate sensitive cell types.