Here, we describe the preparation, structure, and properties of
cryogel sponges, which represent a new type of macroporous
biomaterial for tissue engineering.
Cryogels were produced through freeze-thawing techniques, either from
agarose alone or from
agarose with grafted
gelatin. The aim of this study was to evaluate
agarose cryogel sponges as scaffolds for culturing both isolated pancreatic islets and
insulinoma cells (INS-1E). In order to evaluate the effect of cell entrapment in artificial scaffolds, cell function reflected by insulin secretion and content was studied in cells cultivated for a 2-week period either in culture
plastic plates or in
cryogel sponge disks. Our results show that
tumor-derived INS-1E cells grown either on
plastic or on
cryogels do not differ in their proliferation, morphology,
insulin release, and intracellular
insulin content. However, isolated pancreatic islets cultivated on
cryogels sponge show 15-fold higher basal insulin secretion at 3.0 mM
glucose than islets cultivated on
plastic plates and fail to respond to stimulation with 16.7 mM
glucose. In addition, these islets have about 2-fold lower
insulin content compared to those grown in
plastic plates. It is possible that the cell dysfunction noted in these in vitro experiments is due to the effect of the limited
oxygen supply to the islets cultivated in
cryogel sponge. Further in vivo studies are needed to clarify the nature of such an observation since according to previous reports,
agarose and
gelatin induce new vessel formation supporting enhanced
oxygen supply.