Development of blood extraction system for health monitoring system.

We focus on research to develop a compact human blood sampling device used for the Self Monitoring of Blood Glucose (SMBG). The SMBG comprises: (1) an indentation system using a shape memory alloy (SMA) actuator to force a microneedle through the skin; (2) a micro electrical pumping system to extract blood using a bimorph type piezoelectric microactuator; (3) a biosensor using an enzyme such as glucose oxidase (GOx) to detect and evaluate the amount of glucose in extracted blood. A titanium microneedle the same size as a female mosquito's labium (60 mum outer diameter, 25 mum inner diameter) was produced by the sputter deposition method. The mechanical design of the device was based upon the mosquito's blood sampling mechanism. The blood extraction system worked well. We measured the performance of the principal components: the indentation load for a microneedle of external diameter 100 mum was found to be 0.1 N. The pumping system has an extraction speed of about 2 mul/min for whole blood. This is similar to that achieved by the mosquito.