| Summary: | 碩士 === 南台科技大學 === 機械工程系 === 102 === According to clinical data, the recurrence rate of bladder cancer for a patient after surgery is still high in five years. Currently, using immunoassay with biomarker is the most cost-effective method and fewer burdens for a patient. This paper develops an DEP chip with inter-digital (IDT) electrodes array for immunosensing of T24 cell lysate based on impedance measurement. The DEP chip structure consists of three layers such as Au bottom electrodes on glass substrate, a flow chamber formed by optically clear adhesive (OCA) tape and a top cover glass. Firstly, the Al2O3 nanoparticles were modified by polyaniline (PANDB) and silane for conjugation with galectin-1 antibody as the nanoprobes. Next, these nanoprobes were trapped onto the IDT electrode surface by DEP force, then, the flow chamber was blocked by Bovine Serum Albumin (BSA). After blocking, three different medium such as air, deionized (DI) water and Tween Tris buffered saline (TTBS) was sequentially conducted the impedance measurement before and after immunoassay of T24 lysate. According to the experimental results, the silane-modified scheme is more suitable for preparation of nanoprobes due to its uniformity of immobilization on electrode surface and sensitivity of fluorescence response. When we compare the impedance variation between before and after immunoassay with three different medium, the greatest impedance change can be found as the medium was DI water (10.26 times). For DI water medium, the normalized impedance variation is 3.35 times to control case (only buffer). Consequently, choosing medium is crucial parameter for impedance-based biochip, and our results demonstrated that DI water could be a good candidate as the measurement medium.
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