Self-powered microneedle-based biosensors for pain-free high-accuracy measurement of glycaemia in interstitial fluid

In this work a novel self-powered microneedle-based transdermal biosensor for pain-free high-accuracy real-time measurement of glycaemia in interstitial fluid (ISF) is reported. The proposed transdermal biosensor makes use of an array of silicon-dioxide hollow microneedles that are about one order of magnitude both smaller (borehole down to 4µm) and more densely-packed (up to 1×106needles/cm2) than state-of-the-art microneedles used for biosensing so far. This allows self-powered (i.e. pump-free) uptake of ISF to be carried out with high efficacy and reliability in a few seconds (uptake rate up to 1µl/s) by exploiting capillarity in the microneedles. By coupling the microneedles operating under capillary-action with an enzymatic glucose biosensor integrated on the back-side of the needle-chip, glucose measurements are performed with high accuracy (±20% of the actual glucose level for 96% of measures) and reproducibility (coefficient of variation 8.56%) in real-time (30s) over the range 0–630mg/dl, thus significantly improving microneedle-based biosensor performance with respect to the state-of-the-art. •Self-powered pain-free microneedle-based transdermal biosensor for high-accuracy measurement of glycaemia in interstitial fluid (ISF).•Pump-free (autonomous) reliable, effective, and fast uptake of ISF by exploiting capillarity in tiny hollow microneedles.•FDA compliant real-time measurement of glucose in ISF by coupling microneedles under capillary-action and enzymatic glucose biosensors.•Performance of microneedle-based glucose biosensors in ISF: time 30 s, linearity 0–630 mg/dl, accuracy within ±20% for 96% of measures.