Surface characterization and platelet compatibility evaluation of binary mixed self-assembled monolayers containing novel sulfonic acid terminated alkanethiol

The interactions between the biological environment and artificial surface are greatly influenced by the surface characteristics of substrate. Self-assembled monolayer prepared by long-chain alkanethiol on gold has been considered as a good model surface to study the effects of surface characteristics upon biological responses. In this study, two different series of mixed SAMs prepared by lab-synthesized sulfonic acid terminated alkanethiol with hydrophobic -CH₃ or hydrophilic -OH terminated one were characterized. It was noted that the surface hydrophilicity of -SO₃H/-CH₃ mixed SAMs was increased with the solution mole fraction of -SO₃H terminated thiol. However, the surfaces were all hydrophilic on the -SO₃H/-OH mixed SAMs. All of these mixed SAMs were " -SO₃H poor" and negatively charged on surface. In vitro platelet adhesion study indicated that -SO₃H/-OH mixed SAMs exhibited a better platelet compatibility than -SO₃H/-CH₃ mixed ones, suggesting a surface with fair hydrophilicity and least negative surface charges might be of potential as a candidate for developing a platelet/blood compatible artificial surface.