Browsing by Author "Chang, Pang-Chia"

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Enhanced bioconjugation on sputtered palladium nano-thin-film electrode
(2019-03-04)
Chang, Chia-Yu
;
Chen, Wei
;
Su, Chien-Hao
;
Chang, Pang-Chia
;
Huang, Yun-Tzu
A highly reactive surface with an enhanced ability for chemical bonding relies on the presence of specifically coordinated atoms and step edges at the surface. In this study, an electrode with a unique Stranski-Krastanov-like thin film, with an epitaxial sputtering of a palladium (Pd) nanoparticle double layer on the polyethylene terephthalate substrate, was developed. On the surface of this flexible Pd-nano-thin-film (NTF) electrode with a (1 1 1) containing surface, DNA probes can be quickly immobilized in as short a period as 20 min, which is 24 times faster than that on the gold electrode. A DNA-based anticancer compound (ACC) sensing and screening process that would use the DNA functionalized Pd-NTF electrode as the biosensor was then proposed. Interestingly, the developed biosensor could detect DNA and ACCs, such as doxorubicin, tetra-O-methyl nordihydroguaiaretic acid, and Taxol via interactions with solutions containing 1 mu l ACCs within 11 min, and the sensitivity of the ACC solution is similar to 0.1 mu M (similar to 36 pg per-test), as detected by electrochemical impedance spectroscopy. Moreover, this highly reactive surface can be used in regular sensors and other interfaces, in scientific applications. (C) 2019 Author(s).
Surface active flexible palladium nano-thin-film electrode development for biosensing
(2019-09-01)
Chang, Chia-Yu
;
Huang, Yun-Tzu
;
Chang, Pang-Chia
;
Su, Chien-Hao
;
Hsu, Kuo-Chen
Metal atoms on surface edges or with specific coordinates possess high surface potentials, and serve as core atoms for organic molecule bonding. However, these active metal atoms may lose their activity by self-diffusion on the surface. A polyethylene terephthalate (PET) substrate provided a stable rough surface in nanoscale for metal atoms absorption and formation of a stable and active nano-thin-film (NTF) surface. However, the NTF surface roughness decreased with increasing thickness of palladium (Pd) granules, indicating that the surface growth of the Pd film followed a Stranski-Krastanov-like growth model. Therefore, the proper thickness of Pd-NTF on PET substrate (Pd NTF-PET) was developed for electrochemical impedance spectroscopy (EIS). Protein was immobilized on the Pd NTF-PET electrodes within 15 min and its biosensing sensitivity was as low as 0.1 ng per-test in 1 mu l. We expect that the developed Pd NTF-PET electrode can be used for other biosensing applications as well.
The fabrication and application of Ni-DNA nanowire-based nanoelectronic devices
(2019-06-01)
Chang, Pang-Chia
;
Chang, Chia-Yu
;
Jian, Wen-Bin
;
Yuan, Chiun-Jye
;
Chen, Yu-Chang
DNA is a self-assembled, double stranded natural molecule that can chelate and align nickel ions between its base pairs. The fabrication of a DNA-guided nickel ion chain (Ni-DNA) device was successful, as indicated by the conducting currents exhibiting a Ni ion redox reaction-driven negative differential resistance effect, a property unique to mem-elements (1). The redox state of nickel ions in the Ni-DNA device is programmable by applying an external bias with different polarities and writing times (2). The multiple states of Ni-DNA-based memristive and memcapacitive systems were characterized (3). As such, the development of Ni-DNA nanowire device-based circuits in the near future is proposed.