Evaluation of novel blood-hemoglobin measurement microsystem with integrated processing circuits and Si [110] 45°-mirrors

In this paper, performance of a silicon microsystem for blood hemoglobin measurement is demonstrated, and evaluation of long-term stability with real blood samples is presented. Long optical path is realized inside the microchip using two 45° mirrors of Si [110]. First, the microchips were fabricated and evaluated with food color solution. As a result, effects of optical path extension are clearly shown as minimum resolution improvement. Furthermore, adverse effects due to utilization of the mirrors have not been observed. Durability of the microchip with real blood sample was evaluated. Normal range of human hemoglobin has been covered with linear range of the microchip. In repetitive blood measurement, absorbance has fine coefficient of variation of 0.61 % or less, so the microchip has satisfied resolution for hematological test.