US Patent 7048723 Surface micromachined microneedles

Surface micro-machined micro-needles (32) are formed as single needles (32) or in two-dimensional or three-dimensional micro-needle arrays (30). The micro-needles (32) are fabricated on a substrate (12) which can remain attached to the micro-needles (32) or can be subsequently removed. The two-dimensional or three-dimensional micro-needle arrays (30) can have cross-coupling flow channels (36) which allow for pressure equalization, and balance of fluid flow within the micro-needle arrays (30). Each of the micro-needles (32) has a micro-channel (36) therethrough that provides communication between at least one input port (37) at a proximal end of the micro-needles (32), and at least on output port (39) at an opposite distal end.