Patterning self-assembled monolayers using microcontact printing: a new technology for biosensors?

A biosensor combines two functions: molecular recognition and signal transduction’. The fabrication of a biosensor often requires the properties of surfaces to be tailored and patterned with complex organic functional groups including, for example, ligands for protein recognition, and attachment points for proteins, peptides, carbohydrates and other relevant groups. Convenient, generally applicable methods for producing surfaces are an important part of biosensor technology. The system of self-assembled monolayers (SAMs) of alkanethiolates on gold is probably the best that is currently available to accomplish the fimctionalization and patterning of surfaces required by many applications in biomaterials science (for review, see Ref. 2). The convenience and flexibility of SAMs for this purpose has been widely recognized and exploited, especially for homogeneous surfaces. Their stability meets the requirements of most biosensors. In this article, we describe a new technique microcontact printing (pCP) that allows SAMs to be patterneds. This process can readily generate features down to 1 p,rn in size, and down to 200 nm with difficulty, and is compatible with complex organic functionality. The process also requires little, or no, access to the photolithographic equipment usually required to generate patterns with these dimensions. The combination of SAMs and &P provides a remarkably convenient technology for the preparation ofpatterned surfaces, giving excellent control over surface properties at the molecular level. We believe that this technology will be useful in the production of biosensors.