Fabrication of Stainless Steel Microneedle with Laser-Cut Sharp Tip and its Penetration and Blood Sampling Performance

Abstract

The demand for minimally invasive injection needles or needle-shaped tools is growing from those who carry out medical practices such as blood or insulin injections. Applying the mosquito biomimetic, we have used a femtosecond laser to fabricate minimally invasive microneedles out of ultrafine hollow SUS304 pipes, 50 μm in outer diameter and 20 μm in inner diameter. When such a stainless steel needle tip is angled at 15°, it has the lowest penetration resistance, two and a half times lower than that of the finest hollow needle that is commercially available. A blood suction experiment with a newly developed microneedle has demonstrated that 2.8 μℓ of blood can be drawn out in 20 seconds. Such stainless steel microneedles fabricated by femtosecond lasers have great potential as minimally invasive and mass-producible blood sampling needles to be used for diabetic inspections.