Plasma lithography - thin-film patterning of polymers by RF plasma polymerization II: Study of differential binding using adsorption probes

In this study we present methods to physico-chemically modify micropatterne d cell culture substrates that were manufactured using plasma lithography t o incorporate affinity structures for specific cell binding, The surfaces c onsist of a pattern of a fluorocarbon plasma polymer with feature sizes bet ween 5 and 100 mum on a back-ground of a non-fouling tetraglyme (tetraethyl ene glycol dimethyl ether) plasma polymer. The tetraglyme polymer blocks vi rtually all non-specific binding of proteins, and it is non-adhesive for a fluorocarbon-polyethylene glycol (FC-PEG) surfactant designed to act as a ' hydrophobic anchor' for peptides. The surfactant shows a strong affinity fo r the fluorocarbon polymer pattern, thus enabling us to form a pattern of t he surfactant-conjugated peptide. To verify this, we have synthesized a conjugate between histamine (as a mod el for a more complex peptide) and a commercially available FC-PEG surfacta nt. Disuccinimidyl carbonate was used to activate the terminal -OH group of the polyethylene glycol headgroup for the reaction with the amine-containi ng molecule. Affinity pattern formation can easily be achieved by immersion of the patterned substrates in a solution of the peptide-surfactant conjug ate. Time of flight secondary ion mass spectroscopy in the imaging mode was used to verify that the surfactant localizes on the pattern, while the bac kground remains bare. A model protein, bovine serum albumin, showed the sam e behavior. This suggests that these surfaces can be used for the formation of patterns of cell-adhesive proteins. These substrates will be used to in vestigate the influence of the cell size and shape of vascular smooth muscl e cells on their physiology.