US Patent 7762638 - Hydrophobic barrier for microfluidic channels

http://www.freepatentsonline.com/7762638.html

Over the past decade NanoInk has developed Dip Pen Nanolithography® for applications in maskless nanolithography and bioassays. This is their latest patent specifying a system of ink wells for scanning probe tips which minimize cross-contamination. Claim 1 reads:

1. A microfluidic device comprising:

a substrate comprising a surface and a plurality of microchannels which are hydrophilicly surface treated, and

at least one hydrophobic barrier layer on the surface between the microchannels which prevents cross contamination between the plurality of microchannels when liquid flows through the microchannels,

wherein the hydrophobic barrier layer is a polymeric layer.