Laser fabrication of high aspect ratio thin holes on biodegradable polymer and its application to a microneedle

The present paper reports the fabrication of long thin holes with a high aspect ratio of 100 (diameter: 10 mu m, depth: I mm) in biodegradable polymer material (polylactic acid, referred to herein as PLA) using a UV excimer laser. Holes having diameters of 10, 20 and 50 mu m are fabricated from the side surface of a PLA sheet, and their fabricated shapes are observed using an optical microscope. These holes are compared with holes fabricated in other polymer sheets. It is proven that a long thin hole can be fabricated in PLA material, although at a lower fabrication rate compared that for epoxy material. This laser fabrication is applied to a PLA microneedle, which is fabricated by the micromolding technique. A hole is fabricated along the centerline of the newly developed microneedle, and it is confirmed experimentally that blood plasma is taken into this hole by capillary force. (c) 2006 Elsevier B.V. All rights reserved.