Ratio of Hba1c to Hemoglobin on Ring-shaped Interdigital Electrode Arrays Based on Impedance Measurement

• Main Authors: Wei-LiHu, 胡維禮
• Other Authors: Ling-Sheng Jang
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/57154106884423943454

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 101 === It’s essential to monitor the long-term glucose concentration in the blood of the diabetic patients, and glycated hemoglobin (HbA1c) has became one of the most important mark to diagnose. This study presents an on-chip biosensor for detecting the glycated hemoglobin as a ratio to total hemoglobin (Hb) based on impedance measurement. In the measurement process, no any other reagent is required. It’s label-free, and low sample volume needed. The ring-shaped interdigital electrodes were coated with the self-assembled monolayer (SAM) to immobilize the proteins and measured the before-after impedance deviations via the impedance analyzer. The roughness of glass substrates was further improved by buffer oxide etchant (BOE), and distribution uniformity of the proteins were also improved which was examined by fluorescent images. Various concentrations of Hb and HbA1c were measured via before-after impedance deviations. After HbA1c separation process, the ratio of HbA1c to total Hb was measured by the differential capacitance ΔC of the proteins calculated from the equivalent circuit model. ΔC would rise with the percentage of HbA1c, and was good linearity after 7% in 200 ng/µL Hb and HbA1c. The proposed detection method is much close to actual point-of-care diagnostics to diabetic patients with the advantage of low-cost and easy fabrication.