The stealthy ways of the ubiquitous mosquito got Seiji Aoyagi and his team of micro-engineers at Kansai University in Japan thinking: Could the pest teach them how to build a painless needle? The answer is yes, at least in prototype. Instead of the smooth surface of today’s needles, the team’s syringe is highly serrated, resulting in less needle-to-nerve contact as it penetrates the skin. Aoyagi says the pain-free needle could be available within five years.