The ability of
DNA strands to influence cellular gene expression directly and to bind with high affinity and specificity to other
biological molecules (e.
g., proteins and target
DNA strands) makes them a potentially attractive component of cell culture substrates. On the basis of the potential importance of
immobilized DNA in cell culture and the well-defined characteristics of alkanethiol self-assembled monolayers (
SAMs), the current study was designed to create multifunctional
SAMs upon which cell adhesion and
DNA immobilization can be independently modulated. The approach immobilizes the
fibronectin-derived cell adhesion
ligand Arg-Gly-Asp-Ser-Pro (RGDSP) using
carbodiimide activation chemistry and immobilizes
DNA strands on the same surface via
cDNA-
DNA interactions. The surface density of hexanethiol-terminated
DNA strands on alkanethiol monolayers (30.2-69.2 pmol/cm2) was controlled using a backfill method, and specific target
DNA binding on
cDNA-containing
SAMs was regulated by varying the soluble target
DNA concentration and
buffer characteristics. The
fibronectin-derived cell adhesion
ligand GGRGDSP was covalently linked to carboxylate groups on
DNA-containing SAM substrates, and
peptide density was proportional to the amount of carboxylate present during SAM preparation. C166-GFP endothelial cells attached and spread on mixed SAM substrates and cell adhesion and spreading were specifically mediated by the immobilized GGRGDSP
peptide. The ability to control the characteristics of noncovalent
DNA immobilization and cell adhesion on a cell culture substrate suggests that these mixed
SAMs could be a useful platform for studying the interaction between cells and
DNA.