A novel surfactant-based immobilization method for varying substrate-boundfibronectin

Most biomaterials can be rendered adhesive for anchorage-dependent cells by adsorption of serum, isolated extracellular matrix proteins, or immobiliza tion of peptide sequences. However, difficulties are frequently encountered in characterizing the adsorbed layer due to conformational changes in the molecules following adsorption al td interference from nonspecifically adso rbed molecules. In this study, we have investigated a technique for covalen tly immobilizing fibronectin to the PEG-containing triblock copolymer Pluro nic(TM) F108 ("F108"). We have compared this technique to solution adsorpti on of fibronectin for its ability to provide controlled variation of bound fibronectin and regulation of fibroblast behavior. Both simple adsorption a nd covalent immobilization were effective for varying substrate-bound fibro nectin. However, adsorption of fibronectin did not effectively regulate fib roblast attachment or spreading in either serum-free or serum-containing me dia. Fibroblast attachment, spreading, cytoskeletal organization, and proli feration were effectively regulated in response to fibronectin immobilized to F108. Furthermore, F108-treated surfaces without immobilized fibronectin did not support nonspecific fibroblast attachment, even in the presence of serum-containing medium. Fibroblasts were observed to only proliferate on surfaces with high levels of immobilized fibronectin that supported extensi ve cell spreading and cytoskeletal organization. In summary, covalent immob ilization of fibronectin to F108 provided controlled regulation of fibrobla st behavior without interference from nonspecific protein adsorption, even in the presence of serum-containing medium. (C) 2000 John Wiley & Sons, Inc .