Hydrogels As Cell Carriers For Tissue Engineering

By PreSens Precision Sensing GmbH

Hydrogels might be a new method for cell-based regenerative therapy. They can be applied in a minimal invasive way but they have to be biodegradable and nontoxic. The biocompatibility of different hydrogels seeded with hMSCs was tested in this study. CaO₂ served as an oxygen releasing additive in the gels to overcome oxygen limitations or gradients within the gels. The hydrogels used might be suitable for the future injection of cells in damaged tissue. CaO₂ seems to be an outstanding oxygen releasing additive but cytotoxic side effects are a problem.

Gel-based cell application could be a new and innovative method for healing of tissue defects. Hydrogels mostly consist of aqueous media which are combined with a polymer. They are an alternative to solid cell seeded scaffolds which require surgical application, while gels could be applied minimally invasive by injection. A limiting factor in using hydrogels as cell carriers is the limited oxygen supply to the cells after application of the gel. Adding oxygen releasing additives into the carriers might help overcome oxygen limitation or gradients within the gels. In this study the biocompatibility of different biodegradable hydrogels was tested. The gels are temperature responsive: the polymer is added to culture medium and cells are integrated at room temperature. The solution remains liquid until heated to body temperature - then the gel starts to solidify. CaO₂ was used as an oxygen releasing additive to enhance the oxygen supply to the cells. The resulting formation of H₂O₂ lowered the cell survival rate dramatically. To prevent this effect, catalase was added together with CaO₂ and tests were repeated. Monitoring of the oxygen saturation within the gels was performed using needle-type chemical optical sensors by PreSens.