Biodegradable Polymer Needle Having a Trench for Collecting Blood by Capillary Force

This paper proposes a biodegradable polymer (Poly Lactic Acid, called as PLA) needle having a trench for collecting blood. A solid micro needle of polymer can be fabricated by micromolding method. However, a hollow needle is difficult to be fabricated by this method. It is also difficult to fabricate a long hole with ultra high aspect ratio along the centerline of a micromolded needle. On the other hand, it is comparatively easy to fabricate a trench on a needle surface. Blood runs up along this trench by capillary force, which realizes simple and easy blood collection without pumping mechanism. A needle with straight shank is fabricated by contriving wet etching method of a groove on a silicon die. A trench is fabricated on the top surface of the needle by laser micromachining. The performance of collecting blood of this needle is experimentally evaluated.