Browsing by Author "Chou, Tzu-Ting"

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Functional magnetic nanoparticles-assisted electrochemical biosensor for eosinophil cationic protein in cell culture
(2018-03-01)
Lee, Cheng-Yu
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Wu, Li-Ping
;
Chou, Tzu-Ting
;
Hsieh, You-Zung
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應用化學系
A low-cost electrochemical biosensor, assisted by a new type of functional magnetic nanoparticles (NPs), has been developed to detect eosinophil cationic protein (ECP), a known biomarker of asthma, in cell culture. The heparin-modified magnetic NPs were mixed with a sample solution containing ECP. After ECP had been captured by the NPs, a magnetic field was applied behind a graphite-based screen-printed electrode. The functional magnetic NPs were attracted to the electrode, raising the ECP concentration near its surface. Because of the use of the functional magnetic NPs, the difference in the signal was amplified when applying larger sample volumes for detection, thereby enhancing the sensitivity of the biosensor. This approach provided a linear range for the analysis of the logarithm of the ECP concentration from 1 to 1000 nM, with a coefficient of determination 0.992; the limit of detection was 0.30 nM. The fabricated biosensor displayed good recovery in a cell culture medium incubated with the Beas-2 B cell line. The ability to detect the concentration of ECP in a cell culture at any time point should be useful for explaining contradictory findings regarding the relationship between the initial ECP concentration and the cell line. (c) 2017 Elsevier B.V. All rights reserved.
The investigation of interfacial and crystallographic observation in the Ni(V)/SAC/OSP Cu solder joints with high and low silver content during thermal cycling test
(2015-12-01)
Lee, Christine Jill
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Chen, Wei-Yu
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Chou, Tzu-Ting
;
Lee, Tae-Kyu
;
Wu, Yew-Chung
This study investigated the microstructure and grain orientation of Ni(V)/SAC396/OSP Cu and Ni(V)/SAC105/OSP Cu solder joints during thermal cycling test (TCT). In general, adjusting Ag content in solders influenced the performance of thermal cycling (TC). Nevertheless, it is still crucial to find the optimal condition of Ag and related mechanisms of crack formation during TCT. This study applied FE-SEM to observe the crack propagation and the precipitation of Sn-Ag IMCs in the solders. Moreover, FE-EPMA and EBSD were used to detect the elemental distribution and grain orientation near the cracks, respectively. The locations of crack initiation are strongly related to the CTE mismatch between Si chip and solder alloy. Besides, the large number of Ag3Sn precipitations in the joint with high Ag content efficiently hinder the crack propagation due to the effects of precipitation hardening. It is revealed that the Ni(V)/SAC396/OSP Cu exhibits good thermal stability during thermal cycle test.