This letter describes a technique that can be used to produce well-defined features of gold' The technique involves patterning of a self-assembled monolayer (SAM) on a gold substrate using an elastomer stamp (fabricated either from a phenol-formaldehyde polymer or polydimethylsiloxane), followed by selective etching in an aqueous, basic solution of cyanide ion and dissolved dioxygen (lM KOH, 0.1 M KCN). Electrically conductive structures of gold with dimensions as small as 1 pm have been produced using this procedure. Once a rubber stamp is fabricated, patterning and etching of gold substrates is straightforward. This method is convenient, does not require routine access to clean rooms and photolithographic equipment, and can be used to produce multiple copies of a pattern. 'A. M. Brittan. Anr Sci. 62. 102 (1914).

This paper describes an experimentally simple technique, based on stamping or contact printing, to pattern the adsorption of alkanethiolates on surfaces of gold, on scales from 0.2 to 100 gm, and illustrates the use of these patterned surfaces. An elastomeric stamp, fabricated from poly(dimethylsiloxane) (PDMS), was used to deliver alkanethiol to predetermined regions of the surface of an evaporated gold film. With this technique, organic surfaces patterned with well-defined regions exhibiting different chemical and physical properties have been produced. This technique was used to pattern the adsorption of single and multiple SAMs on a single substrate. This method of preparing patterned surfaces has been used in a variety of applications, including the preparation of well-defined, heterogeneous substrates for scanning probe microscopies, the formation of microelectrodes, the formation of microstructures of silicon, the preparation of substrates for the study of condensation figures, and the preparation of substrates for patterned formation of microcrystals.

An elastomeric stamp, containing defined features on the micrometer scale, was used to imprint gold surfaces with specific patterns of self-assembled monolayers of alkanethiols and, thereby, to create islands of defined shape and size that support extracellular matrix protein adsorption and cell attachment. Through this technique, it was possible to place cells in predetermined locations and arrays, separated by defined distances, and to dictate their shape. Limiting the degree of cell extension provided control over cell growth and protein secretion. This method is experimentally simple and highly adaptable. It should be useful for applications in biotechnology that require analysis of individual cells cultured at high density or repeated access to cells placed in specified locations.

Microcontact printing, is described. It offers extreme experimental simplicity and flexibility, relying on the ability of self‐assembled monolayers (SAMs) of longchain alkanethiolates on gold and other metals to act as nanometer resists. The Figure is an electron micrograph of a silicon microstructure resulting from chemical etching of a patterned SAM.

No abstract