Research On Hollow Out-of-Plane Microneedles Based On Simulating Mosquitoes’ Mouthpart

Microneedle is a miniature product that plays a very important role in the field of medical development to the world. It is mainly used to give patients injection for biological analysis and draw blood from patients for testing. Through understanding the bionic concepts and then choosing the structure and blood sucking movement of mosquitoes as the breakthrough point, MEMS technology was used to make the hollow out-of-plane microneedles array the the holes diameter relatively to the mouthparts of mosquitoes.The combination of dry etching and wet etching was used to fabricate the hollow out-of-plane microneedles array. Specifically, dry etching was used to etch the hole throughout, but it is difficult to achieve the aspect of35:1only etching from one side of the wafer and also difficult to make the hole wall too coarse to sample. Therefore, two-step etching and DRIE from both sides of the wafer were used to etch the boreholes completely and to ensure the holes have lateral smoothness. Microneedles composed of{411} exterior crystal planes were formed by anisotropic etching in40%KOH solution at a water-bath temperature of87degrees. Finally, hollow silicon microneedles with a shank height of100μm-120μm and the needle borehole diameter of10μm-25μm were fabricated.Sample tests performed using pig skin and have shown that the microneedles have sufficient strength. The microneedles, that we fabricated by using MEMS, have potential applications in painless transdermal drug delivery systems (TDDS).