Development of Microneedle Puncture Device that Prevents Buckling of Needle by Delivery Operation

Abstract

Herein, using the micromachining technology, we propose a microneedle delivery mechanism that is similar to the lead delivery mechanism for a mechanical pencil. This mechanism involves three parts: a needle grasping part, a needle advancing part, and a needle retainer. This mechanism advances the needle by repeating the following steps: 1) fix the needle in the grasping part; 2) simultaneously advance the grasping part and the needle using the advancing part; 3) release the needle from the grasping part; 4) retreat the grasping and the advancing parts to their initial positions. This operation advances the needle very slowly, thereby allowing the needle to puncture the skin without buckling, even if the needle has a narrow diameter. Each component of the puncture device was cut from a plastic plate using a femtosecond laser. We evaluated the performance of the device for a stainless steel needle of φ100 μm, and were successful in delivering the needle at approximately 100 μm/cycle under a no-load condition. We also succeeded in puncturing the same needle into a hydrogel (Young’s modulus of ∼0.08 MPa) using this device.