Abstract 3978: Cell proliferation and cell localization following in situ immobilization in a 3D alginate foam matrix
Authors: Melvik Jan Egil , Andersen Therese , Heier-Baardson Helene , Dornish Michael 
Published: February 2011

Abstract
Cells cultured in a 3 dimensional matrix should approximate the cell architecture and cell-cell contact as found in tissues, organs and tumors. However, many 3D matrices don't provide such a culture environment. We have developed an alginate-based foam matrix for culturing cells in 3D whereby cells are immobilized within and throughout the foam matrix by in situ gelation.
Mouse myoblasts C2C12 (ATCC CRL-1772) were cultured in 2D and prepared as a suspension of 1.0% sodium alginate in DMEM medium. 125 µl cell suspensions were added to γ-sterilized NovaMatrix 3DTM foams fitted to 24-well culture plates at cell densities of 10,000 or 25,000 cells/foam. As the cell suspension was absorbed by the foam matrix, calcium ions diffused from the foam and gelling of the alginate solution occurred by ionic cross-linking, thereby effectively entrapping the cells within the pores of the foam. At different time points cell proliferation was measured by degelling the foam by incubating in 50 mM sodium citrate. Cells were recovered by centrifugation and counted using an automatic cell counter. Cell localization within the foam was visualized using a confocal microscope to identify cells fluorescently labeled cells using a carboxyfluorescein marker.
The C2C12 myoblasts proliferated slower when immobilized within the alginate foam matrix compared to a standard 2D tissue culture. Despite the reduced proliferation rate, the cells were found to be viable. For cells immobilized within an alginate gel, the alginate may not provide necessary attachment factors for cells to stimulate proliferation. We investigated the use of the cell attachment peptide RGD coupled to the immobilizing alginate and its effect on proliferation of cells within the alginate foam. After two days of culture, the foam with RGD-coupled alginate had three times as many myoblasts as the plain alginate foam. A uniform distribution of cells throughout the thickness of the foam was confirmed by confocal microscopy.
Use of alginate foams with concomitant in situ immobilization of cells results in a 3D model with the potential to approximate cell proliferation and architecture within tissues or tumors. The cell proliferation rate can effectively be promoted by addition of cell attachment peptides such as RGD. The elasticity of the NovaMatrix 3DTM system can be varied by changing type and concentration of immobilizing alginate for specific cell lines and stem cell differentiation. The immobilized cells can be treated with drugs or other agents in cell survival or cytotoxicity experiments since the alginate matrix is permeable for small and medium sized molecules. Cells can be recovered by de-gelling the foam with EDTA or citrate enabling downstream processing. The foam may also be implanted as a xenograft, making the NovaMatrix 3DTM system truly versatile.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3978.