276g Effect of Structural Variations In Porous Scaffolds on Cell Growth

Pooja Iyer and Sundararajan V. Madihally. Chemical Engineering, Oklahoma State University, 423 Engineering North, Oklahoma State University, Stillwater, OK 74078-5021

The demand for organs or tissue transplants is more than the supply. This has created the need to find alternate structures that can mimic the properties of the body tissues. These alternate structures which are artificially engineered should be porous, degradable, bindable to the target organ and conducive to cell growth in human body. The first three factors have been widely studied and reported in literature. Cell growth in both chitosan and chitosan-gelatin tissues need to be studied and compared in greater detail. The emphasis needs to be on reproducing the growth of these tissues in human body and recreating conditions that are similar to the human body. This includes the use of serum free media to grow the cells.

In our experiments, chitosan and chitosan-gelatin scaffolds, with 2D and 3D architectures were constructed to determine the growth of human fibroblasts on these porous structures, which were cultured using serum free media. These structures were first quantified for mechanical properties and results showed a broad range of elastic modulus (2 Pa to 2,000,000 P). Hence they were utilized to assess the effect of material properties in the absence and presence of cell-binding domains. Human foreskin fibroblasts seeded on these structures in serum free medium were analyzed using MTT assay. Further, the cytoskeletal structure of the tissue was analyzed using actin staining. Collagen assay was also performed to investigate the viability of these tissues. The analysis was done on the 1st day, 4th day and 7th day after cell seeding.

In preliminary experiments, cytoskeletal organization of human fibroblasts on chitosan structures was found to be minimal. Chitosan gelatin scaffolds demonstrated better organization of the cells on them as indicated by pictures taken after actin staining. Experiments were also carried out on chitosan hydrogels to investigate if the change in structure could aid in better cell growth than in the 3D porous chitosan structure. The results indicate little effect on cytoskeletal structure confirming the fact that a blend of chitosan gelatin is needed to aid in cell growth when conditions similar to those found in the human body is encountered.