Versatile Cell-Specific Ligand Arrangement System onto Desired Compartments of Biodegradable Matrices for...

A promising approach for the regeneration of tissues or organs with three-dimensional hierarchical structures is the preparation of scaffold-cell complexes that mimic these hierarchical structures. This requires an effective technique for immobilizing cell-specific ligands at arbitrarily chosen positions on matrices. Here, we report a versatile system for arranging cell-specific ligands onto desired compartments of biodegradable matrices for site-selective cell arrangement. We utilized the specific binding abilities of specific DNAs, immobilizing them as tags to arrange cell-recognition ligands at desired areas of the matrices by specific binding with cell-recognition ligand-DNA conjugates. We synthesized poly(l-lactide) (PLLA), a biodegradable polymer, with an oligo-DNA (trimer of deoxyguanosine: dG₃) attached via a poly(ethylene glycol) (PEG) spacer to generate dG₃-PEG-b-PLLA. The peptides Arg-Gly-Asp-Ser (RGDS) and Arg-Glu-Asp-Val (REDV) were chosen as cell-recognition ligands and were attached to an adapter DNA (aDNA), which can specifically bind to the dG₃ moiety through G-quadruplex formation. The obtained dG₃-PEG-b-PLLA was deposited on a small spot of the PLLA film, and the aDNA-RGDS or aDNA-REDV conjugate was added on the film to immobilize these ligands at the spot. We confirmed the specific adhesion of L929 cells (a mouse fibroblast cell line) and human umbilical vein endothelial cells (HUVECs) on the small areas coated with dG₃-PEG-b-PLLA in the presence of aDNA-RGDS and aDNA-REDV, respectively, even after applying shear stress by flowing medium across the spot. Cell-specific attachment of the target cells was effectively achieved in a spatially controlled manner. This technique has the potential for the construction of cell-scaffold complexes that mimic the hierarchical structures of natural organs and may represent a breakthrough in realizing regenerative medicine and tissue engineering of complex organs.