Abstract
Paying attention to mosquito proboscis as an ideal model of painless needle, a mosquito penetrating motion was observed in detail using a system comprising high-speed camera system and magnification lens with long working distance. The following facts were proven, i) the mosquito proboscis is composed of plural needles, two of which, i.e., maxillae, have jagged protrusions along its tip area, ii) the central labrum, which plays an important role of sucking blood, and the side two maxillae, are advanced alternatively with certain time phase to each other, the vibration of which is at several Hz, while the total three needles are gradually forward. Imitating precisely the shape and the size of these three needles, microneedles were fabricated using micromachining technique. The puncture forces of three needles against an artificial polymer skin were measured, proving that the cooperative alternative motion is much effective for reducing the necessary force for penetrating the skin, compared to the non-cooperative motion.
