Cell adhesion to mixed self-assembled monolayers carrying different terminal functional groups

We examined relationship between wettability and cell adhesion by taking advantage of self-assembled monolayers (SAMs) of alkanethiols. The SAMs presenting a wide range of wettabilities were prepared by mixing two kinds of alkanethiols carrying terminal methyl (CH₃), hydroxyl (OH), carboxylic acid (COOH), and amino groups (NH₂). The adhesion of human umbilical vein endothelial cells (HUVEC) in a serum-containing medium was greatly influenced by surface functional groups on mixed SAMs: cells adhered to CH₃/COOH and CH₃/NH₂ mixed SAMs with decreasing water contact angle, whereas cells adhered to CH₃/OH mixed SAM showing the maximum at a water contact angle of around 40°. The surface plasmon resonance measurement showed that serum proteins from a culture medium adsorbed on all kinds of the mixed SAM surfaces examined, suggesting quantity, composition and conformation of underlying adsorbed protein layer determine cell adhesion to the surface.