Enhanced Bio-Assays by Using Gradient Nanotopography

A system and method for using gradient nanotopography to increase mammalian cell attachment and cell confinement on surfaces. A surface platform consisting of a thin film of gold possessing a gradient of topography on the surface and self-assembled monolayers of alkanethiols presenting desired functional groups is formed. A gradient in the chemical properties is induced in the terminal groups of the monolayer because of the continuous increase in the surface area and the anisotropy of gold film structure. The gradient nanotopraphy provides simultaneous control of two key properties, the presentation of the terminal functional groups and a continuous increase in the surface density of functional groups on the surface. This control provides for drug screening assays using adherent cell-based experiments.