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Indian IIT  professor Suman Chakraborty (from Indian Institute of Technology, Kharagpur) and Kazuyoshi Tsuchiya of Tokai University in Kanagawa have developed a painless microneedle that can be used medically.

It can be used for giving painless drug injections, to take blood for testing and forthings like a wristwatch-type diabetic glucose monitor.

A female mosquito sucks human blood by contractng and relaxing some muscles in its long needle-like thingie called proboscis. This creates suction (or negative pressure) that draws blood into its mouthparts. Contrary to popular belief, a mosquito bite does not hurt. It is the anticoagulant saliva that the creature injects to stop your blood clotting that causes inflammation and pain.

In the new design, sucking action is provided by a micro electromechanical pump, which works using a piezoelectric actuator attached to the needle.

In contrast to previous microneedles, which were made of silicon dioxide, the new device is robust because it is made of stronger titanium and related alloys, which dramatically reduces the risk of it snapping during injections.

The needle is also strong enough to penetrate as far as 3 millimetres into skin and reach capillary blood vessels.

Its size compared to earlier models also means that surface tension effects are exploited further, and the same capillary flow that draws water up into trees helps draw blood into the microneedle.

The researchers have calculated that their needle can extract 5 microlitres of blood per second. This volume is sufficient for measuring blood-sugar levels in diabetics using a glucose sensor that can be attached to the needle in a “wristwatch” design.