Silicon micromachined hollow microneedles for transdermal liquid transfer

This paper presents an improved design and fabrication process for hollow micro needles with the proper mechanical strength and sharpness to be applied for painless transdermal transfer of liquids. Tests have shown that liquids like blood are drawn into the needle by capillary forces, reducing the need for active pumping. The fabrication method allows different needle shapes like blades and pencils, is robust enough to be applied for larger scale production, and enables the development of a complete micro-TAS for e.g. blood analysis.