Browsing by Author "Pang, See-Tong"

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Label-free Detection of Prostate Specific Antigen Using a Silicon Nanobelt Field-effect Transistor
(2012-05-01)
Wu, Chi-Chang
;
Pan, Tung-Ming
;
Wu, Chung-Shu
;
Yen, Li-Chen
;
Chuang, Cheng-Keng
In this study, we proposed a silicon nanobelt field-effect transistor (FET) to detect prostate specific antigen (PSA). The nanobelt FET device displayed n-channel depletion characteristics. The immobilization of prostate specific antibody (anti-PSA) molecules was attached onto the nanobelt FET surface by using the aldehyde groups of glutaraldehyde linked to the amino groups of 3-aminopropyltriethoxysilane (APTES). The shift in the drain current vs time curves of a nanobelt FET biosensor revealed that the electrical signal had a logarithmic relationship with respect to the concentration of the PSA, and detection capability was estimated in the 5 pg/mL level. To enhance the sensitivity of a nanobelt FET biosensor, this biosensor was designed by inserting arginine molecules between glutaraldehyde and APTES. Therefore, the detection capability of the developed sensor was extended to 50 fg/mL. Also, the relationship between the current shift and the logarithm of PSA concentration was exhibited linearity in the range 50 fg/mL - 500 pg/mL. The excellent electrical results of this label-free PSA nanobelt FET biosensor suggested that such biosensor might be potentially useful tools for biological research and future prostate cancer screening.
Real-Time and Label-Free Detection of the Prostate-Specific Antigen in Human Serum by a Polycrystalline Silicon Nanowire Field-Effect Transistor Biosensor
(2013-08-20)
Huang, Yu-Wen
;
Wu, Chung-Shu
;
Chuang, Cheng-Keng
;
Pang, See-Tong
;
Pan, Tung-Ming
In this research, we used a polycrystalline silicon nanowire field-effect transistor (poly-Si NWFET) as a biosensor that employs the sidewall spacer technique instead of an expensive electron beam lithography method. When compared with commercial semiconductor processes, the sidewall spacer technique has the advantages of simplicity and low cost. hi this study, we employed a novel poly-Si NWFET device for real-time, label-free, and ultrahigh-sensitivity detection of prostate-specific antigen (PSA) in human serum. Since serum proteome is very complex containing high levels of salts and other interfering compounds, we hereby developed a standard operating procedure for real-sample pretreatment to keep a proper pH value and ionic strength of the desalted serum and also utilized Tween 20 to serve as the passivation agent by surface modification on the NWFET to reduce nonspecific binding for medical diagnostic applications. We first modified 3-aminopropyltriethoxysilane on the surface of a poly-Si nanowire device followed by glutaraldehyde functionalization, and the PSA antibodies were immobilized on the aldehyde terminal. While PSA was prepared in the buffers to maintain an appropriate pH value and ionic strength, the results indicated that the sensor could detect trace PSA at less than 5 fg/mL in a microfluidic channel. The novel poly-Si NWFET is developed as a diagnostic platform for monitoring prostate cancer and predicting the risk of early biochemical relapse.
Surface Cleaning of the Nanowire Field-Effect Transistor for Gene Detection
(2011-12-01)
Wu, Chi-Chang
;
Liu, Fu-Ken
;
Lin, Ling-Hung
;
Pang, See-Tong
;
Chuang, Cheng-Keng
The efficiency of DNA immobilization by using various surface cleaning methods is studied in this work. The degree of surface cleaning is evaluated by the surface tension measurement to reveal the contribution from the polar and apolar terms. The observation from the fluorescent microscope images indicates the effectiveness of surface clean by the acetone and ethanol mixtures, as well as the sulphuric acid and hydrogen peroxide mixtures. We also fabricate a series of back-gated, 60-nm nanowired (NW) field-effect transistor (FET) sensors for mutation gene detection by following the developed acetone and ethanol mixtures. Electrical properties of the NWFET sensor demonstrate the n-channel depletion characteristics. The current of the sensor is reduced once the attachment of negative charge molecules. The single-stranded capture DNA is chemically immobilized onto the surface of silicon NWFET by three-step reactions. The sensor surface demonstrates the great performance of current shift after the suitable cleaning. The NWFET sensor is successfully applied to detect the BRAF(V599E) mutation genes from the hybridized processes. The sensing behaviour estimated from the electrical signal reaches the femtomolar level.
Ultrasensitive semiconductor biochip for cancer marker detection
(2010-08-01)
Ko, Fu-Hsiang
;
Chuang, Cheng-Keng
;
Pang, See-Tong
;
Pan, Tung-Ming
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材料科學與工程學系