Browsing by Author "Lin, Chih-Heng"

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A CMOS Capacitive Dopamine Sensor with Sub-nM Detection Resolution
(2009)
Wang, Shi-Wei
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Lu, Michael S. -C.
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生物科技學系
Interdigitated microelectrodes integrated with CMOS sensing circuitry are presented in this work for detection of the neurotransmitter dopamine and as an immunosensor with sensitivity enhanced by gold nanoparticles. Microelectrodes covered by the silicon dioxide layer are fabricated through a maskless post-CMOS process. Charged biomolecules bind to the functionalized oxide surface after immobilization, producing a capacitive change for the underlying electrodes. Three electrode designs with gaps from 0.5 mu m to 1 mu m and capacitance values from 13 fF to 925 IF are tested. The capacitance increases with respect to the concentrations of nanoparticle and dopamine. The minimum detectable concentration of dopamine is 540 pM at a 1-Hz bandwidth.
A nano switch mechanism for the redox-responsive sulfotransferase
(2012-07-15)
Lin, Chih-Heng
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Lin, En-Shyh
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Su, Tian-Mu
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Hung, Kuo-Sheng
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Yang, Yuh-Shyong
Cellular redox signaling is important in diverse physiological and pathological processes. The activity of rat phenol sulfotransferase (rSULT1A1), which is important for the metabolism of hormone and drug, is subjected to redox regulation. Two cysteines, Cys232 and Cys66, nanometer away from each other and from the enzyme active site were proposed to form disulfide bond to regulate the activity of rSULT1A1. A nano switch, composed of a flexible loop from amino acid residues 59-70, explained how this long distance interaction between two cysteines can be achieved. The enzyme properties were investigated through site-directed muatagnesis, circular dichroism, enzyme kinetics and homologous modeling of the rSULT1A1 structures. We proposed that the formation of disulfide bond between Cys232 and Cys66 induced conformational changes of sulfotransferase, then in turn affected its nucleotide binding and enzyme activity. This discovery was extended to understand the possible redox regulation of other sulfotransferases from different organisms. The redox switch can be created in other redox-insensitive sulfotransferases, such as human phenol sulfotransferase (hSULT1A1) and human alcohol sulfotransferase (hSULT2A1), to produce mutant enzymes with redox regulation capacity. This study strongly suggested that redox regulation of drug and hormone metabolism can be significantly varied even though the sequence and structure of SULT1A1 of human and rat have a high degree of homology. (C) 2012 Elsevier Inc. All rights reserved.
An electrochemical dopamine sensor with a CMOS detection circuit
(2008-07-01)
Chan, Feng-Lin
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Chang, Wen-Ying
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Kuo, Li-Min
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Lin, Chih-Heng
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Wang, Shi-Wei
This paper presents the integration of interdigitated microelectrodes and a CMOS circuit for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with a gap of 3 mu m are fabricated by the lift-off technique. The CMOS sensing circuit has a current gain of 10, an integrating capacitor of 4 pF, and a measured dynamic range of 60 dB. The applied reduction and oxidation potentials are determined by voltammetry at about -0.2 V and 0.6 V, respectively. The measured collection efficiency can reach up to 84%. The produced oxidation current with respect to dopamine concentration averages 0.44 nA mu M(-1).
An electrochemical dopamine sensor with CMOS detection circuit
(2007-01-01)
Zhan, Feng-Lin
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Kuo, Li-Min
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Wang, Shi-Wei
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Lu, Michael S. -C.
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Chang, Wen-Ying
This paper presents the use of interdigitated microelectrodes as the platform for electrochemical sensing of the neurotransmitter dopamine. Gold electrodes with gaps ranging between 3 gm to 7 gm are fabricated by the lift-off technique. The reduction and oxidation potentials for dopamine are determined by voltammetry using the fabricated microelectrodes. A CMOS sensing circuit is used to amplify the electrochemical current produced by the working electrodes. Experimental result shows that for a dopamine concentration of 10 mu M the measured current value is 11 pA.
Connecting IM Pattern and Selective Perceived Responsiveness to Relationship: A Cluster-Based Approach
(2019-01-01)
Lee, Hao-Ping
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Chen, Kuan-Yin
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Lin, Chih-Heng
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Chang, Yung-Ju
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交大名義發表
As people utilize instant messaging (IM) to communicate with people of various relationships, they pay different amounts of attention to and have different communication practices with them of different relationships. However, we haven't seen a close investigation of how users' IM communication patterns relate to different groups of IM contacts. We collected IM logs of 547 sender-recipient pairs from 33 smartphone users over the course of 4 weeks, and used k-mean clustering to identify 6 clusters of these users' IM communication patterns. We illustrate the characteristics of the IM patterns of these distinct clusters as well as how the patterns relate to the relationship between the senders and the recipients within these clusters respectively.
Connecting IM Pattern and Selective Perceived Responsiveness to Relationship: A Cluster-Based Approach
(2019-01-01)
Lee, Hao-Ping
;
Chen, Kuan-Yin
;
Lin, Chih-Heng
;
Chang, Yung-Ju
;
交大名義發表
As people utilize instant messaging (IM) to communicate with people of various relationships, they pay different amounts of attention to and have different communication practices with them of different relationships. However, we haven't seen a close investigation of how users' IM communication patterns relate to different groups of IM contacts. We collected IM logs of 547 sender-recipient pairs from 33 smartphone users over the course of 4 weeks, and used k-mean clustering to identify 6 clusters of these users' IM communication patterns. We illustrate the characteristics of the IM patterns of these distinct clusters as well as how the patterns relate to the relationship between the senders and the recipients within these clusters respectively.
Does Who Matter? Studying the Impact of Relationship Characteristics on Receptivity to Mobile IM Messages
(2019-01-01)
Lee, Hao-Ping
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Chen, Kuan-Yin
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Lin, Chih-Heng
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Chen, Chia-Yu
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Chung, Yu-Lin
This study examines the characteristics of mobile instant-messaging users' relationships with their social contacts and the effects of both relationship and interruption context on four measures of receptivity: Attentiveness, Responsiveness, Interruptibility, and Opportuneness. Overall, interruption context overshadows relationship characteristics as predictors of all four of these facets of receptivity; this overshadowing was most acute for Interruptibility and Opportuneness, but existed for all factors. In addition, while Mobile Maintenance Expectation and Activity Engagement were negatively correlated with all receptivity measures, each such measure had its own set of predictors, highlighting the conceptual differences among the measures. Finally, delving more deeply into potential relationship effects, we found that a single, simple closeness question was as effective at predicting receptivity as the 12-item Unidimensional Relationship Closeness Scale.
Electrodeless dielectrophoretic concentrator for analyte pre-concentration on poly-silicon nanowire field effect transistor
(2013-03-01)
Puttaswamy, Srinivasu Valagerahally
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Lin, Chih-Heng
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Sivashankar, Shilpa
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Yang, Yuh-Shyong
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Liu, Cheng-Hsien
The sensitivity of biosensors can be affected by mass transport limitations as a result of miniaturization. To enhance signal sensitivity, pre-concentration of deoxyribonucleic acid (DNA), in the vicinity of the sensing elements of n-type polycrystalline silicon nanowire field effect transistor (Poly-Si NWFET) is demonstrated using a microfluidic device based on insulator or gradient dielectrophoresis (iDEP) to overcome mass transport limitations. In insulator-based dielectrophoresis (iDEP), insulating microstructures produce non-uniform electric fields to drive dielectrophoresis (DEP) in microsystems. Fabrication of accurately controlled three-dimensional (3D) microstructure of poly (ethylene glycol) diacrylate (PEG-DA) with a narrow microchannel using maskless gray-scale lithography is described. The fabrication of three-dimensional structures at low cost with saving time is accomplished by the use of maskless exposure system. PEG-DA has been used due to its excellent biocompatibility and ease of fabrication. To enhance the stability of PEG-DA, we added another polymer pentaerythritol tetraacrylate (PETA). Electrical property of the Poly-Si NWFET is ensured by plotting I-V-G curve after the integration of iDEP micro device. (c) 2013 Elsevier B.V. All rights reserved.
Manipulating Polycrystalline Silicon Nanowire FET Characteristics by Light Illumination
(2016-03-17)
Chen, Chien-Hung
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Hwang, Chi-Hung
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生物科技學系
Polycrystalline silicon nanowire field-effect transistor (poly-SiNW FET) has attracted many attentions in the past decade because of its ultrasensitive, label-free, and real-time response for potential sensing applications particular for biosensors. In this paper, the changes of the electric characteristics of poly-SiNW FET introduced by light illumination are studied systematically. Particularly, the red light (635 nm) and UV light (365 nm) are employed as light sources. Both lights are projected on the poly-SiNW FETs installed and are tested in air or in a vacuum (0.1 Ton) chamber. The results show that both light sources can change the electric characteristics of poly-SiNW FET which indicates that the photoelectronic effect can manipulate both n- and p-type devices of poly-SiNW FET; meanwhile, results also support the potential of poly-SiNW FET in air and in the vacuum environment for optoelectronic sensing applications.
Novel poly-silicon nanowire field effect transistor for biosensing application
(2009-01-01)
Hsiao, Cheng-Yun
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Lin, Chih-Heng
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Hung, Cheng-Hsiung
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Su, Chun-Jung
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Lo, Yen-Ren
A simple and low-cost method to fabricate poly-silicon nanowire field effect transistor (poly-Si NW FET) for biosensing application was demonstrated. The poly-silicon nanowire (poly-Si NW) channel was fabricated by employing the poly-silicon (poly-Si) sidewall spacer technique, which approach was comparable with current commercial semiconductor process and forsaken expensive E-beam lithography tools. The electronic properties of the poly-Si NW FET in aqueous solution were found to be similar to those of single-crystal silicon nanowire held effect transistors reported in the literature. A model biotin and avidin/streptavidin sensing system was used to demonstrate the biosensing capacity of poly-Si NW FET. The changes Of ID-VG curves were consistent with an n-type FET affected by a nearby negatively (streptavidin) and positively (avidin) charged molecules, respectively. Specific electric changes were observed for streptavidin and avidin sensing when nanowire surface of poly-Si NW FET was modified with biotin and streptavidin at sub pM to nM range could be distinguished. With its excellent electric properties and the potential for mass commercial production, poly-Si NW FET can be a very useful transducer for a variety of biosensing applications. (C) 2008 Elsevier B.V. All rights reserved.
Poly-silicon nanowire field-effect transistor for ultrasensitive and label-free detection of pathogenic avian influenza DNA
(2009-06-15)
Lin, Chih-Heng
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Hung, Cheng-Hsiung
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Hsiao, Cheng-Yun
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Lin, Horng-Chih
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Ko, Fu-Hsiang
Enhanced surveillance of influenza requires rapid, robust. and inexpensive analytical techniques capable of providing a detailed analysis of influenza virus strains. Functionalized poly-crystalline silicon nanowire field-effect transistor (poly-SiNW FET) was demonstrated to achieve specific and Ultrasensitive (at fM level) detection of high pathogenic strain virus (H5 and H7) DNA of avian influenza (AI) which is an important infectious disease and has an immediate need for surveillance. The poly-SiNW FET was prepared by a simple and low-cost method that is compatible with Current commercial semiconductor process without expensive E-beam lithography tools for large-scale production. Specific electric changes were observed for AI virus DNA sensing when nanowire surface of poly-SiNW FET was modified with complementary captured DNA probe and target DNA (H5) at fM to pM range Could be distinguished. With its excellent electric properties and potential for mass commercial production, poly-SiNW FET car, be developed to become a portable biosensor for field use and point-of-care diagnoses. (C) 2009 Elsevier B.V. All rights reserved.
Predicting Smartphone Users' General Responsiveness to IM Contacts Based on IM Behavior
(2019-01-01)
Lee, Hao-Ping
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Chung, Yu-Lin
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Dingier, Tilman
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Chen, Chia-Yu
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Lin, Chih-Heng
History of conversations through instant messaging (IM) contains abundant information about the communication patterns of the dyad, including conversation partners' mutual responsiveness to messages. We have, however, not seen many examinations of using such information in modeling mobile users' responsiveness in IM communication. In this paper, we present an in-the-wild study, in which we leverage participants' IM messaging logs to build models predicting their general responsiveness. Our models based on data from 33 IM user achieved an accuracy of up to 71% (AUROC). In particular, we show that 90-day IM-communication patterns, in general, outperformed their 14-day equivalent in our prediction models, indicating better coherence between long-term IM patterns with their general communication experience.
Preparation of Silicon Nanowire Field-effect Transistor for Chemical and Biosensing Applications
(2016-04)
Wu, Jennifer Yun-Shin
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Lin, Chih-Heng
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Feng, Mei-Huei
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Chen, Chien-Hung
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Su, Ping-Chia
Surveillance using biomarkers is critical for the early detection, rapid intervention, and reduction in the incidence of diseases. In this study, we describe the preparation of polycrystalline silicon nanowire field-effect transistors (pSNWFETs) that serve as biosensing devices for biomarker detection. A protocol for chemical and biomolecular sensing by using pSNWFETs is presented. The pSNWFET device was demonstrated to be a promising transducer for real-time, label-free, and ultra-high-sensitivity biosensing applications. The source/drain channel conductivity of a pSNWFET is sensitive to changes in the environment around its silicon nanowire (SNW) surface. Thus, by immobilizing probes on the SNW surface, the pSNWFET can be used to detect various biotargets ranging from small molecules (dopamine) to macromolecules (DNA and proteins). Immobilizing a bioprobe on the SNW surface, which is a multistep procedure, is vital for determining the specificity of the biosensor. It is essential that every step of the immobilization procedure is correctly performed. We verified surface modifications by directly observing the shift in the electric properties of the pSNWFET following each modification step. Additionally, X-ray photoelectron spectroscopy was used to examine the surface composition following each modification. Finally, we demonstrated DNA sensing on the pSNWFET. This protocol provides step-by-step procedures for verifying bioprobe immobilization and subsequent DNA biosensing application.
Recovery Based Nanowire Field-Effect Transistor Detection of Pathogenic Avian Influenza DNA
(2012-02-01)
Lin, Chih-Heng
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Chu, Chia-Jung
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Teng, Kang-Ning
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Su, Yi-Jr
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Chen, Chii-Dong
Fast and accurate diagnosis is critical in infectious disease surveillance and management. We proposed a DNA recovery system that can easily be adapted to DNA chip or DNA biosensor for fast identification and confirmation of target DNA. This method was based on the re-hybridization of DNA target with a recovery DNA to free the DNA probe. Functionalized silicon nanowire field-effect transistor (SiNW FET) was demonstrated to monitor such specific DNA-DNA interaction using high pathogenic strain virus hemagglutinin 1 (H1) DNA of avian influenza (AI) as target. Specific electric changes were observed in real-time for AI virus DNA sensing and device recovery when nanowire surface of SiNW FET was modified with complementary captured DNA probe. The recovery based SiNW FET biosensor can be further developed for fast identification and further confirmation of a variety of influenza virus strains and other infectious diseases. (C) 2012 The Japan Society of Applied Physics
Sloped-Gate Voltage Method for Improving Measurement of Poly-Si Nanowire FET in Aqueous Environment
(2013-05-02)
Chen, Chien-Hung
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Su, Yi-Jr
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Lin, Chih-Heng
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Liao, Tai-Shan
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Yang, Yuh-Shyong
Nanowire field-effect transistors are suited to. study the activity of biomolecules in bionanotechnology. The changes of biomolecules process are efficiently affected the charge at the nanowire surface; thus, the electrical characterization of NW-FET is Changed. Although NW-FET is a well-known device in bioapplications, however, the intrinsic electrical characterization of NW-FET effect, on real electrical measurement is not well studied. We present herein a novel measurement method to avoid errors in electrical characteristic of nanowire field-effect transistors. A physical model is developed to explore the effect of the leakage current, which is influenced by the charging effect of an equivalent capacitor in a NW-FET. We also present a sloped-gate voltage method to reduce the effect, of equivalent capacitor in air, liquid, and phosphate buffered solution. The application of the sloped gate voltage Method significantly increases the stability of electrical characterization measurements. This method can also be easily applied to biosensing experiments.
Spatially reinforced Au nano-cavities as a reaction nano-reservoir for trace analysis of DNA hybridization
(2014-02-01)
Yao, Chih-Kai
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Liao, Jiunn-Der
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Yu, Sheng-Hong
Spatially reinforced Au nano-cavities (SR-nAu) with reduced tip-to-tip displacement create strongly localized surface plasmon resonance by Raman scattering. Within SR-nAu, the nano-cavity structure with high aspect ratio was optimized as the nano-reservoir for the distinction of DNA hybridization responses from specific DNA sequences of Avian influenza virus. In the nano-reservoir, the suspended or immobilized probe, its complementary and noncomplementary target sequences were characterized at very low concentration through enhanced Raman spectra. The presence of Raman shift at 738 cm(-1), the characteristic breathing mode of thymine, and the change of relative peaks intensity at 1603 and 1554 cm(-1) before and after hybridization were particularly taken as the major indications to validate the match or mismatch state of DNA sequences. Through a labeling-free means, and from the evidence provided by specific complementary and noncomplementary DNA sequences, the recognition capability of nano-reservoir can be down to subnano-molar concentration (10(-10) M). (C) 2013 Elsevier B.V. All rights reserved.
Surface composition and interactions of mobile charges with immobilized molecules on polycrystalline silicon nanowires
(2015-05-01)
Lin, Chih-Heng
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Feng, Mei-Huei
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Hwang, Chi-Hung
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Wu, Jennifer Yun-Shin
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Su, Ping-Chia
The polycrystalline silicon nanowire field-effect transistor (poly-SiNW FET) is one of the most sensitive sensors used in real-time and label-free biosensing applications. Its low power requirement, mass production potential, and integrability with electronic components make it a highly attractive device in the rapidly growing diagnostic research field. From the viewpoint of device physics, the charges in the vicinity of a nanowire (NW) surface modulate the electrical characteristics of the NW device. The charges can originate from surface molecules or an ionic solution, and their role in NW biosensing systems remains to be clarified. Determining their role is crucial for understanding the physical interactions of charges in a biosensing event and for the realization of NW-based biosensors. Therefore, using poly-SiNW FET, we investigated the interactions of the immobilized molecules on the NW surface with the mobile charges in solutions. We also investigated the interactions between the mobile charged polymers and the immobilized molecules on the NW surface, and we observed the effect of charge neutrality, originating from Coulomb charge-charge interactions, on the NW conductance. Finally, the isoelectric points between native and sulfated PSGL-1 peptides on the NW surface were identified. This study provides a physical understanding of the charge-charge interaction of mobile charges with immobilized charged molecules on a nanoscale surface and presents new opportunities for using charge-based detection in biological and chemical sensing applications. (C) 2015 Elsevier B.V. All rights reserved.
Ultrasensitive and label-free detection of pathogenic avian influenza DNA by using CMOS impedimetric sensors
(2012-05-15)
Lai, Wei-An
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Lu, Michael S. -C.
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生物科技學系
This work work presents miniaturized CMOS (complementary metal oxide semiconductor) sensors for non-faradic impedimetric detection of AIV (avian influenza virus) oligonucleotides. The signal-to-noise ratio is significantly improved by monolithic sensor integration to reduce the effect of parasitic capacitances. The use of sub-mu m interdigitated microelectrodes is also beneficial for promoting the signal coupling efficiency. Capacitance changes associated with surface modification, functionalization, and DNA hybridization were extracted from the measured frequency responses based on an equivalent-circuit model. Hybridization of the AIV H5 capture and target DNA probes produced a capacitance reduction of -13.2 +/- 2.1% for target DNA concentrations from 1 fM to 10 fM, while a capacitance increase was observed when H5 target DNA was replaced with non-complementary H7 target DNA. With the demonstrated superior sensing capabilities, this miniaturized CMOS sensing platform shows great potential for label-free point-of-care biosensing applications. (C) 2012 Elsevier B.V. All rights reserved.
ULTRASENSITIVE DETECTION OF AVIAN INFLUENZA VIRUS BY USING CMOS IMPEDIMETRIC SENSOR ARRAYS
(2012)
Lai, Wei-An
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Lu, Michael S. -C.
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生物科技學系
This work presents miniaturized CMOS (complementary metal oxide semiconductor) impedimetric sensors for detection of avian influenza virus (AIV) in the femto-molar level. The sensing resolution is significantly enhanced owing to monolithic sensor integration to reduce the parasitic effect and the use of sub-mu m interdigitated microelectrodes to promote signal coupling efficiency. The 4x4 sensor array contains four electrode designs of different sizes. Capacitance changes associated with surface modification, functionalization, and DNA hybridization were extracted from measured frequency responses based on an equivalent circuit. Hybridization of AIV H5 capture and target DNA produced a percentage capacitance change of -12.8+/-3% among the four designs for target DNA concentrations from 1 fM to 10 fM, while capacitance increases were observed for non-specific binding of the H5 and H7 DNA probes.
Ultrasensitive detection of dopamine using a polysilicon nanowire field-effect transistor
(2008)
Lin, Chih-Heng
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Hsiao, Cheng-Yun
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Hung, Cheng-Hsiung
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Lo, Yen-Ren
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Lee, Cheng-Che
An unprecedented high sensitive sensing of neurotransmitter dopamine at fM level was demonstrated using a poly-crystalline silicon nanowire field-effect transistor (poly-SiNW FET) fabricated by employing a simple and low-cost poly-Si sidewall spacer technique, which was compatible with current commercial semiconductor processes for large-scale standard manufacture.