A new instrument for automated microcontact printing with stamp load adjustment

An instrument for automated microcontact printing (mu CP) on microscope slides is described. The movement of the stamp, which is actuated by a computer controlled pneumatic actuator, is precisely guided until it makes contact with the substrate. As a consequence, the absolute position of the microprinted patterns is reproducible over a series of substrates with 1 mu m standard deviation. Exchange of substrates and stamps is a quick and simple procedure. This makes possible the microprinting of adjacent or superimposable patterns, with different products, in a reproducible manner. Furthermore, a novel approach is described for adjusting the load on the stamp during contact. Two adjustable screws are set up so that their length (with reference to the substrate holder) limits the stamp compression during contact. The load on the stamp is proportional to the stamp compression and from the experimental point of view, this is controlled by the operator adjusting the screws. This makes possible the mu CP with stamps incorporating large surface features as well as stamps with isolated features raised on the surface. For proof of concept, automated mu CP of a single parallelepiped polydimethylsiloxane feature, with a surface of 2 cmx30 mu m and a height of 25 mu m, is demonstrated inside a microfluidic channel without roof collapse. A second example is provided with a single cross feature, possessing an overall surface of 140x140 mu m(2) and a height of 14 mu m. Potential applications of this versatile, inexpensive and compact instrument are discussed. The machine's potential for high throughput also makes it suitable for mass production applications. (c) 2008 American Institute of Physics.