Development of automatic blood extraction device with a micro-needle for blood-sugar level measurement

In this study, a portable type HMS (Health Monitoring System) device is newly developed. It has features 1) puncturing a blood vessel by using a minimally invasive micro-needle, 2) extracting and transferring human blood and 3) measuring blood glucose level. This miniature SMBG (Self-Monitoring of Blood Glucose) device employs a syringe reciprocal blood extraction system equipped with an electro-mechanical control unit for accurate and steady operations. The device consists of a) a disposable syringe unit, b) a non-disposable body unit, and c) a glucose enzyme sensor. The syringe unit consists of a syringe itself, its cover, a piston and a titanium alloy micro-needle, whose inner diameter is about 100 m. The body unit consists of a linear driven-type stepping motor, a piston jig, which connects directly to the shaft of the stepping motor, and a syringe jig, which is driven by combining with the piston jig and slider, which fixes the syringe jig. The required thrust to drive the slider is designed to be greater than the value of the blood extraction force. Because of this driving mechanism, the automatic blood extraction and discharging processes are completed by only one linear driven-type stepping motor. The experimental results using our miniature SMBG device was confirmed to output more than 90% volumetric efficiency under the driving speed of the piston, 1.0mm/s. Further, the blood sugar level was measured successfully by using the glucose enzyme sensor.