Micromachined pipette arrays (MPA)

The design and biocompatibility testing of batch fabricated micromachined pipette arrays is described. The process used to fabricate the metallic micromachined pipette arrays (MPA) includes p/sup +/ etch-stop membrane technology, anisotropic etching of silicon in potassium hydroxide, sacrificial thick photoresist micromolding technology, and micro electroforming technology. Arrays of one to ten pipettes have been fabricated using nickel as the structural material and gold as the biocompatible coating of inside walls. The inner dimensions of the individual pipettes fabricated to date range from 30 /spl mu/m to 1.5 mm in width, 0.5 mm to several cm in length, and 5 /spl mu/m to 50 /spl mu/m in thickness. The micromachined pipettes have many advantages over current micro pipette technology, including: (a) highly parallel manipulation of samples/reagents, (b) the capability to precisely define the pipette dimensions allowing for small volumes (in pL to /spl mu/L range), and (c) a wide range of pipette center-to-center spacings (from centimeters to approximately 20 /spl mu/m).