Browsing by Author "Chang, K. S."

Now showing 1 - 2 of 2

A possibility of detection of the non-charge based analytes using ultra-thin body field-effect transistors
(2008-07-15)
Sheu, J. -T.
;
Chen, C. C.
;
Chang, K. S.
;
Li, Y. -K.
;
材料科學與工程學系奈米科技碩博班
Ultra-thin body of p-type field-effect transistors were developed as transducer for biosensors. Changes of conductance resulted from the changes of the surface potentials of ultra-thin body field-effect transistors (UTB-FETs) due to surface chemical modifications were demonstrated. The channel surface of UTB-FETs were modified with N-[3-(trimethoxysilyl)propyl]ethylenediamine (AEAPTMS) and then gold nanoparticles (AuNPs) to immobilize the bio-component, the genetically engineered Delta(5)-3-ketosteroid isomerase (Art_KSI) or the Art_KSI conjugated with charged reporter (Art_KSI_mA51). The binding of charge-based molecules or nanoparticles has been demonstrated to strongly affect the conductivity of UTB-FETs: the increase or decrease of the conductance depends on the polarity of the immobilized molecules or nanoparticles. A new protocol involving the detection of a non-charged analyte relied on the competitive binding of analyte (19-norandrostendione) and a charged reporter (mA51) with KSL When exposed to a 19-norandrostendione solution (10 mu M), the conductance of Art_KSI_mA51-modified UTB-FET increased by 265 nS (similar to 12%). On the other hand, conductance of Art_KSI_modified UTB-FET showed no distinct change under the same detection conditions. (c) 2008 Elsevier B.V. All rights reserved
Enhancement of electrochemical properties of screen-printed carbon electrodes by oxygen plasma treatment
(2009-08-30)
Wang, S. C.
;
Chang, K. S.
;
Yuan, C. J.
;
生物科技學系
;
Department of Biological Science and Technology
Plasma treatment is frequently used to clean and modify the surface of materials, including polymers and graphite. However, very limited information has been reported concerning the modification of a matrix. such as a screen-printed carbon electrode (SPCE) which is consisted of a mixture of graphite and pasting binder, using plasma. In this study. the surface characteristics and electrochemical properties of the plasma-treated SPCEs were investigated. The plasma-treated SPCEs performed a good electrochemical response (enhanced about 80-fold compared with those untreated electrode) and exhibited good reproducibility (CV of 4.8%). The response of plasma-treated electrodes was comparable with the electrodes modified with noble metal and superior to those electrode modified with carbon nanotube (CNT) (ca. 20-fold). SEM imaging revealed that an effective decomposition or removal of impurities and pasting binder on the surface of SPCEs during oxygen plasma treatment. The plasma treatment increases the step-like defects on the surfaces of graphite particles resulting in the generation of numerous edge planes. The phenomena could be responsible for the improvement of the electrochemical properties of SPCEs. The results also suggest that the plasma treatment condition is important. Over-erosion on the SPCE surface by high powered plasma may lead to the poor reproducibility of the SPCEs. (C) 2009 Elsevier Ltd. All rights reserved.