Combined Harpoonlike Jagged Microneedles Imitating Mosquito's Proboscis and Its Insertion Experiment with Vibration

Abstract

Imitating the mosquito's proboscis, the combined microneedles comprising a central straight needle and two outer jagged needles have been already proposed by the authors, and the effectiveness of these needles for easy insertion was investigated by the finite element method (FEM) simulation. Following this, in the present paper, silicon microneedles are practically fabricated by using a silicon on insulator (SOI) wafer and deep reactive ion etching (DRIE) process. A sole straight needle, a sole jagged needle, and combined jagged needles are employed. The fabricated shape and size of the harpoon‐like jagged protrusions are almost the same as the mosquito's. The resistance force during inserting these fabricated needles into an artificial skin of silicone rubber is experimentally investigated. Comparing the results, the effect of combining needles for easy insertion is confirmed. It is also confirmed that applying vibration to the needles with jagged shape is fairly effective for easy insertion. The mechanisms of employing jagged shape needles, applying vibration, and combining needles are discussed. For practical medical applications, a silicon needle is not safe enough on the human body owing to its brittleness. To cope with this problem, coating the silicon surface with biocompatible parylene is proposed. It is proved that parylene‐coated needle surely penetrates silicone rubber, although the necessary force increases. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Mechanisms of ovipositor insertion and steering of a parasitic wasp

“…Low forces were also suggested to occur during puncturing (55) and further insertion (57) of a mosquito proboscis. The low force values are partially attributed to the oscillatory movements of individual elements (55,58). The forces estimated in this study are the sum of all forces acting on the ovipositor valves and can therefore not be directly compared with those in the mosquito experiments.…”

Realistic imitation of mosquito's proboscis: Electrochemically etched sharp and jagged needles and their cooperative inserting motion

“…16(a). We previously made clear in experimental way that the friction force between polymer and silicone rubber is apparently larger than that between silicon and silicone rubber [6]. The large friction force maybe prevents the force drop at the puncture of polymer needle.…”

“…The authors also previously fabricated a needle with two-and-half-dimensional sharper tip by using deep reactive ion etching (DRIE) [5,6]: however, a three-dimensional sharp tip, i.e., conically sharp tip, was still difficult to fabricate. To overcome above-mentioned problem, in this paper, a silicon microneedle having both the three-dimensional sharp tip and the harpoon-like jagged shank is fabricated by employing electrochemical etching technique, which has never used for sharpening the silicon needle tip, although there is a report of sharpening the tip of Pt-Ir wire for the probe of scanning tunnel microscope (STM) [7].…”

Tissue Cutting With Microserrated Biopsy Punches

“…The mosquito's maxilla represents an optimal model for low insertion force and efficient penetration [7]. Imitating its jagged outer shape has the potential to lead to significant benefits.…”

“…Atkins and several other researchers [4][5][6] have already performed some preliminary studies related to the presence of serrated cutting edges that mimic certain animal features, such as the mosquito's proboscis, stinger of bees, and fish teeth. Izumi et al [7] have studied the performances of insertions executed with silicon microneedles that mimic the mosquito's maxilla. Similar needles were also realized by Aoyagi et al [8] and Oka et al [9].…”