Patterning colloidal nanotopographies

Creating a device where cell reactions to nanoscale topographies and a control (usually planar) surface can be monitored simultaneously is advantageous from a biological perspective. Through the utilization of both natural lithography and conventional photolithography techniques, it has been possible to create a structure where planar and nanopillared surfaces lie collaterally on one device. By patterning an optical resist, exposing this to the desired mask pattern, developing and coating in poly- L -lysine, a surface adhesive to gold colloidal particles is presented. Following immersion in a colloidal sol, in this case a 20 nm diameter gold colloidal sol, colloids adhere to the poly- L -lysine across the primed surface. In a subsequent dry etch step, the colloids that are present where the resist has been removed act as an etch mask, resulting in pillars being etched into the surface of a base substrate, in this instance either silicon or quartz. By removing the resist and also the colloids, a device results where planar and nanopillared areas lie collaterally. This allows cell reactions on the two surfaces to be monitored simultaneously.