(323a) Ex-Vivo Tissue Engineering in Inverted Colloidal Crystal Scaffolds with Nanostructured Surface Coating from Organic-Inorganic Composite

Experimental data from a variety of groups and in a variety of tissues point to the fact that 3D organization of cells is critical for their proper functioning in ex-vivo conditions. Recently we introduced a new type of 3D scaffolds that makes possible (1) standardization of cell development conditions; (2) highly reproducible and ordered 3D architecture, (3) easy interrogation by spectroscopic means, and (4) simplicity of surface functionalization with a variety of bioactive molecules. They are made on the basis of inverted colloidal crystals (Figure 1) made from either silicate of hydrogel. The key problem of the hydrogel scaffold, such as poor adhesion of cells, was successfully solved by using layer-by-layer modification of the scaffold surface with nanostructured films of montmorillonite clay. The nanocomposite nature of the coating makes possible (1) its successful coupling with the hydrogel matrix, (2) transparency; and (3) high local Young modulus on the surface necessary for efficient adhesion of many cells. Successful demonstration of co-cultures of hematopoietic cells was demonstrated. The combination of adherent bone marrow HS5 cells with dispersed CD34+ stem cells resulted in the ex-vivo reproduction of bone marrow functions, such as cell differentiation and B-cell production. Variations in the nanostructured coating was also demonstrated to affect the lineage choice for CD34+ stem cell differentiation.