FABRICATING LARGE ARRAYS OF MICROWELLS WITH ARBITRARY DIMENSIONS AND FILLING THEM USING DISCONTINUOUS DEWETTING

This paper describes the fabrication of large (up to 45 cm(2)) arrays of microwells, with volumes as small as similar to 3 fL/well and densi ties as high as 10(7) wells/cm(2). These arrays of microwells are form ed by casting an elastomer, poly(dimethylsiloxane) (PDMS), against ''m asters'' prepared by photolithography; arrays of microwells in other p olymers can be formed by using a master consisting of posts in PDMS. A straightforward technique, discontinuous dewetting, allows wells to b e filled rapidly (typically on the order of 10(4) wells/s) and uniform ly with a wide range of liquids. Several rudimentary strategies for ad dressing microwells are investigated, including electroosmotic pumping and gaseous diffusion.