Browsing by Author "Wu, Ching-Yi"

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3D 65nm CMOS with 320 degrees C Microwave Dopant Activation
(2009)
Lee, Yao-Jen
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Lu, Yu-Lun
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Hsueh, Fu-Kuo
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Huang, Kuo-Chin
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Wan, Chia-Chen
For the first time, CMOS TFTs of 65nm channel length have been demonstrated by using a novel microwave dopant activation technique. A low temperature microwave anneal is. demonstrated and discussed in this study. We have successfully activated the poly-Si gate electrode and source/drain junctions, BF2 for p-MOS TFTs and P-31 for n-MOS TFTs at a low temperature of 320 degrees C without diffusion. The technology is promising for high performance and low cost upper layer nanometer-scale transistors as required by low temperature 3D-ICs fabrication.
Amorphous-Layer Regrowth and Activation of P and As Implanted Si by Low-Temperature Microwave Annealing
(2011-07-01)
Hsueh, Fu-Kuo
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Lee, Yao-Jen
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Lin, Kun-Lin
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Current, Michael I.
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Wu, Ching-Yi
Microwave annealing of dopants in Si has been reported to produce highly activated junctions at temperatures far below those needed for comparable results using conventional thermal processes. However, the details of the kinetics and mechanisms for microwave annealing are far from well understood. In this paper, 20-keV arsenic (As) and 15-keV phosphorus (P) implants, in a dose range from 1 to 5 x 10(15) ion/cm(2), were annealed by microwave methods at temperatures below 500 degrees.C. These junctions were characterized by profile studies with secondary ion mass spectrometry and spreading resistance profiling, sheet resistance with four-point probe, and extensive use of cross-sectional transmission electron microscopy to follow the regrowth of the as-implanted amorphous layers created by the implantation. The amorphous-layer regrowth was observed to be uneven in time, with relatively little amorphous/crystalline interface motion for less than 50 s, followed by rapid regrowth for longer times. Sheet resistance values continued to drop for anneal times after the regrowth process was complete, with some evidence of dopant deactivation for anneal times of 600 s.
Detection of Staphylococcus aureus by Functional Gold Nanoparticle-Based Affinity Surface-Assisted Laser Desorption/Ionization Mass Spectrometry
(2015-02-17)
Lai, Hong-Zheng
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Wang, Sin-Ge
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Wu, Ching-Yi
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Chen, Yu-Chie
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應用化學系
Staphylococcus aureus is one of the common pathogenic bacteria responsible for bacterial infectious diseases and food poisoning. This study presents an analytical method based on the affinity nanoprobe-based mass spectrometry that enables detection of S. aureus in aqueous samples. A peptide aptamer DVFLGDVFLGDEC (DD) that can recognize S. aureus and methicillin-resistant S. aureus (MRSA) was used as the reducing agent and protective group to generate DD-immobilized gold nanoparticles (AuNPs@DD) from one-pot reactions. The thiol group from cysteine in the peptide aptamer, i.e., DD, can interact with gold ions to generate DD-immobilized AuNPs in an alkaline solution. The generated AuNPs@DD has an absorption maximum at similar to 518 nm. The average particle size is 7.6 +/- 1.2 nm. Furthermore, the generated AuNPs@DD can selectively bind with S. aureus and MRSA. The conjugates of the target bacteria with AuNPs were directly analyzed by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). The gold ions generated from the AuNPs@DD anchored on the target bacteria were monitored. Gold ions (m/z 197 and 394) were only generated from the conjugates of the target bacterium-AuNP@DD in the SALDI process. Thus, the gold ions could be used as the indicators for the presence of the target bacteria. The detection limit of S. aureus using this method is in the order of a few tens of cells. The low detection limit is due to the ease of generation of gold cluster ion derived from AuNPs under irradiation with a 355 nm laser beam. Apple juice mixed with S. aureus was used as the sample to demonstrate the suitability of the method for real-world application. Because of its low detection limit, this approach can potentially be used to screen the presence of S. aureus in complex samples.
Dextran-encapsulated photoluminescent gold nanoclusters: synthesis and application
(2014-06-17)
Chiu, Wei-Ju
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Chen, Wei-Yu
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Lai, Hong-Zheng
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Wu, Ching-Yi
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Chiang, Hsiang-Lin
Dextrans are widely used as additives in food, pharmaceutical, and cosmetics because of their hydrophilicity, biocompatibility, and low toxicity. These features allow the use of dextrans to modify the surface of nanoparticles to improve cell compatibility for biomedical applications. Additionally, dextran molecules covalently bound with fluorescent dyes are frequently used as tracers in animal studies. These facts show that dextrans are useful compounds for biomedicine-related applications and research. Our aim was to explore a facile way to generate dextran-derived nanoparticles with photoluminescent property for the use in fluorescence imaging of bacteria and cancer cells. Dextran-encapsulated gold nanoclusters (AuNCs@ dextran) were generated through a one-pot reaction by stirring dextrans and aqueous tetrachloroauric acid overnight. The generated AuNCs exhibit bright and green photoluminescence under the illumination of an ultraviolet lamp (lambda(max) = 365 nm), and high cell biocompatibility was found as well. Therefore, the generated AuNCs can be used as fluorescence tracers and nanoprobes. We explored the suitability of AuNCs@ dextran as labeling agents for bacteria, such as Staphylococcus aureus and Escherichia coli. After the bacteria were labeled by AuNCs@ dextran, they became quite visible under a fluorescence microscope. Additionally, we demonstrated that nanocomposites composed of AuNCs@ dextran and silica beads can be readily internalized by cancer cells. The nanocomposites can be readily detected in the cells through their photoluminescence, suggesting possible applications in drug delivery and fluorescence imaging.
Dopant Activation in Single-Crystalline Germanium by Low-Temperature Microwave Annealing
(2011-02-01)
Lee, Yao-Jen
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Chuang, Shang-Shiun
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Hsueh, Fu-Kuo
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Lin, Ho-Ming
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Wu, Shich-Chuang
Phosphorus activated in germanium epitaxy atop Si wafer by low-temperature microwave annealing technique was investigated in this letter. Compared to the conventional RTA process, the temperature of phosphorus activation could be 120 degrees C to 140 degrees C which is an improvement in temperature reduction at the same sheet resistance. According to the SRP, up to 150 degrees C reduction in maximum temperature at the same activation concentration (about 2 x 10(19) cm(-3)) could be achieved. Through adjusting the microwave power and process time, sheet resistance could be decreased while suppressing dopant diffusion. In addition, the inserted susceptor wafers above and below the processing wafer also suppressed the dopant diffusion and improved film roughness.
Functional gold nanoparticle-based antibacterial agents for nosocomial and antibiotic-resistant bacteria
(2016-10)
Kuo, Yen-Ling
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Wang, Sin-Ge
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Wu, Ching-Yi
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Lee, Kai-Chieh
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Jao, Chan-Jung
Aim: Medical treatments for bacterial-infections have become challenging because of the emergence of antibiotic-resistant bacterial strains. Thus, new therapeutics and antibiotics must be developed. Materials & methods: Arginine and tryptophan can target negatively-charged bacteria and penetrate bacterial cell membrane, respectively. Synthetic-peptides containing arginine, tryptophan and cysteine termini, in other words, (DVFLG) 2 REEW 4 C and (DVFLG) 2 REEW 2 C, as starting materials were mixed with aqueous tetrachloroauric acid to generate peptide-immobilized gold nanoparticles (i.e., [DVFLG] 2 REEW 4 C-AuNPs and [DVFLG] 2 REEW 2 C-AuNPs) through one-pot reactions. Results & discussion: The peptide immobilized AuNPs exhibit targeting capacity and antibacterial activity. Furthermore, (DVFLG) 2 REEW 4 C-AuNPs immobilized with a higher number of tryptophan molecules possess more effective antibacterial capacity than (DVFLG) 2 REEW 2 C-AuNPs. Nevertheless, they are not harmful for animal cells. The feasibility of using the peptide-AuNPs to inhibit the cell growth of bacterium-infected macrophages was demonstrated. Conclusion: These results suggested that the proposed antibacterial AuNPs are effective antibacterial agents for Staphylococci, Enterococci and antibiotic-resistant bacterial strains.
High Tensile Stress with Minimal Dopant Diffusion by Low Temperature Microwave Anneal
(2011)
Lee, Yao-Jen
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Lu, Yu-Lun
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Mu, Zheng-Chang
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Hsueh, Fu-Kuo
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Chao, Tien-Sheng
In this letter, rapid thermal annealing (RTA) and microwave annealing (MA) are compared to demonstrate the dopant activation. Using microwave annealing, the dopant in the Si was well-activated and showed suppressed dopant diffusion, as compared to traditional high temperature RTA. In addition, SiN(x) films after low temperature MA treatment presented higher tensile stress than the films annealed by RTA. Therefore, this MA approach could potentially be applied to these behaviors of I distribution and higher tensile stress SiNx film may be useful in contact etch-stop layer or stress memorization technique in the fabrication of small pitch nanoscaled n-channel Metal-Oxide-Semiconductor Field Effect Transistors. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3536462] All rights reserved.
Magnetic Nanoparticle-Based Platform for Characterization of Shiga-like Toxin 1 from Complex Samples
(2015-10-20)
Kuo, Fang-Yin
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Chang, Bo-Yao
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Wu, Ching-Yi
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Mong, Kwok-Kong Tony
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Chen, Yu-Chie
Foodbome illness outbreaks resulting from contamination of Escherichia call O157:H7 remain a serious concern in food safety. E. coli O157:H7 can cause bloody diarrhea, hemolytic uremic syndrome, or even death. The pathogenicity of E. coli O157:H7 is mainly caused by the expression of Shiga-like toxins (SLTs), i.e., SLT-1 and SLT-2. SLTs are pentamers composed of a single A and five B subunits. In this study, we propose a magnetic nanoparticle (MNP)-based platform to rapidly identify SLT-1 from the complex cell lysate of E. coli O157:H7. The core of the MNPs is made of iron oxide, whereas the surface of the core is coated with a thin layer of alumina (Fe3O4@Al2O3 MNPs). The Fe3O4@Al2O3 MNPs are functionalized with pigeon ovalbumin (POA), which contains Gal-alpha(1 -> 4)-Gal-beta(1 -> 4)-GlcNAc termini that can bind SLT-1B selectively. Furthermore, POA is a phosphate protein. Thus, it can be easily immobilized on the surface of the Fe3O4@Al2O3 MNPs through aluminum phosphate chelation under microwave heating within 1.5 min. The generated POA-Fe3O4@Al2O3 MNPs are capable of effectively enriching SLT-1B from complex cell lysates simply by pipetting 20 mu L, of the sample in and out of the tip in a vial for similar to 1 min. To release SLT-1 from the MNPs, Gal-alpha(1 -> 4)-Gal disaccharides were used for displacement. The released target species are sufficient to be identified by matrix-assisted laser desorption/ionization mass spectrometry. Although the sample volume used in this approach is small (20 mu L) and the enrichment time is short (1 mm), the selectivity of this approach toward SLT-1B is quite good. We have demonstrated the effectiveness of this approach for rapid determination of the presence of SLT-1 from complex cell lysates and ham/juice samples based on the detection of SLT-1B.
Nanoscale p-MOS Thin-Film Transistor With TiN Gate Electrode Fabricated by Low-Temperature Microwave Dopant Activation
(2010-05-01)
Lu, Yu-Lun
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Hsueh, Fu-Kuo
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Huang, Kuo-Ching
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Cheng, Tz-Yen
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Kowalski, Jeff M.
In this letter, nanoscale p-MOS TFTs with a TiN gate electrode were realized using a novel microwave (MW) dopant-activation technique. We compared both low-temperature MW annealing and rapid thermal annealing. We successfully activated the source/drain region and suppressed the short-channel effects using low-temperature MW annealing. This technique is promising from the viewpoint of realizing high-performance and low-cost upper layer nanoscale transistors required for low-temperature 3-D integrated circuit fabrication.
One-Step Detection of Major Lipid Components in Submicroliter Volumes of Unpurified Liposome and Cell Suspensions
(2016-07-19)
Chen, Ssu-Ying
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Wu, Ching-Yi
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Chen, Yu-Chie
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Urban, Pawel L.
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應用化學系
Liposomes and cells have high lipid contents, which are the main components of the external and internal membranes. Mass spectrometry (MS) is widely used in the analysis of the lipids present in the biological matrixes. However, MS analysis of liposome and cell suspensions is challenging due to the presence of other high-abundance matrix components (e.g., salts, buffers, and growth media) that cause ion suppression. These interfering species would normally be removed by dialysis or centrifugation. Here we propose a simple and fast method to detect major lipid components in cells and cell suspensions by MS while circumventing dialysis and centrifugation. Capillary hydrodynamic chromatography (HDC) has been coupled online with the aid of an electrospray ionization (ESI) interface to an ion-trap mass spectrometer. Complex samples containing biopartides and a large amount of potential interferences (buffer, inorganic salts, amino acids) were separated hydrodynamically, detected optically (by light absorption/scattering), and immediately transferred to the MS interface. Liposomes and animal cells are disintegrated during electrospray, and the constituent lipids are ionized. The signal-to-noise ratios are similar to 10x higher in HDC-ESI-MS than in direct infusion ESI-MS experiments (with or without dilution). This method has been tested on liposomes (containing phosphatidylcholine and phosphatidylglycerol) and four types of animal/human cells, i.e., mouse macrophages (RAW 264.7), human breast cancer cells (T47D and HsS78T), and mouse preadipoc-yte cells (3T3-L1). We suggest that HDC-ESI-MS can be used in quality control analyses of bioparticle suspensions in the fields of biotechnology, molecular biology, drug discovery, and cosmetics.
Potent Antibacterial Nanoparticles for Pathogenic Bacteria
(2015-01-28)
Lai, Hong-Zheng
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Chen, Wei-Yu
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Wu, Ching-Yi
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Chen, Yu-Chie
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應用化學系
Antibiotic-resistant bacteria have emerged because of the prevalent use of antibacterial agents. Thus, new antibacterial agents and therapeutics that can treat bacterial infections are necessary. Vancomycin is a potent antibiotic. Unfortunately, some bacterial strains have developed their resistance toward vancomycin. Nevertheless, it has been demonstrated that vancomycin-immobilized nanoparticles (NPs) are capable to be used in inhibition of the cell growth of vancomycin-resistant bacterial strains through multivalent interactions. However, multistep syntheses are usually necessary to generate vancomycin-immobilized NPs. Thus, maintaining the antibiotic activity of vancomycin when the drug is immobilized on the surface of NPs is challenging. In this study, a facile approach to generate vancomycin immobilized gold (Van-Au) NPs through one-pot stirring of vancomycin with aqueous tetrachloroauric acid at pH 12 and 25 degrees C for 24 h was demonstrated. Van-Au NPs (8.4 +/- 1.3 nm in size) were readily generated. The generated Van-Au NPs maintained their antibiotic activities and inhibited the cell growth of pathogens, which included Gram-positive and Gram-negative bacteria as well as antibiotic-resistant bacterial strains. Furthermore, the minimum inhibitory concentration of the Van-Au NPs against bacteria was lower than that of free-form vancomycin. Staphylococcus aureus-infected macrophages were used as the model samples to examine the antibacterial activity of the Van-Au NPs. Macrophages have the tendency to engulf Van-Au NPs through endocytosis. The results showed that the cell growth of S. aureus in the macrophages was effectively inhibited, suggesting the potential of using the generated Van-Au NPs as antibacterial agents for bacterial infectious diseases.
Revisiting the quantitative features of surface-assisted laser desorption/ionization mass spectrometric analysis
(2016-10-28)
Wu, Ching-Yi
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Lee, Kai-Chieh
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Kuo, Yen-Ling
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Chen, Yu-Chie
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應用化學系
Surface-assisted laser desorption/ionization (SALDI) coupled with mass spectrometry (MS) is frequently used to analyse small organics owing to its clean background. Inorganic materials can be used as energy absorbers and the transfer medium to facilitate the desorption/ionization of analytes; thus, they are used as SALDI-assisting materials. Many studies have demonstrated the usefulness of SALDI-MS in quantitative analysis of small organics. However, some characteristics occurring in SALDI-MS require certain attention to ensure the reliability of the quantitative analysis results. The appearance of a coffee-ring effect in SALDI sample preparation is the primary factor that can affect quantitative SALDI-MS analysis results. However, to the best of our knowledge, there are no reports relating to quantitative SALDI-MS analysis that discuss or consider this effect. In this study, the coffee-ring effect is discussed using nanoparticles and nanostructured substrates as SALDI-assisting materials to show how this effect influences SALDI-MS analysis results. Potential solutions for overcoming the existing problems are also suggested. This article is part of the themed issue \'Quantitative mass spectrometry\'.
Riboflavin immobilized Fe3O4 magnetic nanoparticles carried with n-butylidenephthalide as targeting-based anticancer agents
(2019-01-01)
Wu, Ching-Yi
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Chen, Yu-Chie
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應用化學系
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Department of Applied Chemistry
n-Butylidenephthalide (BP) is a potential anti-cancer drug, which can be extracted from Angelica sinensis (Danggui). Previous reports have shown the effectiveness of BP in treating cancer diseases. However, BP has no targeting capacity towards specific cancer cells. To improve treatment efficiency and reduce the dose of BP used in cancer treatment, targeting-based approaches should be developed. In the present study, we used riboflavin-5'-phosphate (RFMP) immobilized iron oxide magnetic nanoparticles (Fe3O4 MNPs) as carriers for BP to treat cancer cell lines derived from liver, prostate and breast. These model cancer cells overexpress riboflavin receptors on their cell membrane and are also sensitive to BP treatment. Thus, BP-binding free RFMP on MNPs can be used as probes to target these model cells, whereas BP can be readily released on target cancer cells. Cell viability was twofold lower by using Fe3O4@RFMP MNPs immobilized with BP than that achieved by using free-form BP at a similar amount. Moreover, BP-Fe3O4@RFMP MNPs have no apparent harmful effects on non-target cells. In addition, we evaluated the level of cysteine-aspartic acid protease 3 (caspase 3) in the resultant cell lysate obtained after treatment by BP-Fe3O4@RFMP MNPs to demonstrate that apoptosis is mainly involved in the growth inhibition of target cells. [GRAPHICS] .
Selective extraction of n-butylidenephthalide from Angelica sinensis (Danggui) by using functionalized iron oxide magnetic nanoparticles as trapping probes
(2018-04-14)
Wu, Ching-Yi
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Wu, Min-Li
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Chen, Yu-Chie
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應用化學系
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Department of Applied Chemistry
n-Butylidenephthalide (BP) is an active compound in Angelica sinensis (Danggui) and a potential anti-cancer drug. Thus, purification of BP from complex herb extract samples is important. In this study, we develop a facile method for selective purification of BP from complex samples by using iron oxide magnetic nanoparticles (Fe3O4 MNPs) immobilized with riboflavin-50-phosphate (RFMP) as affinity probes. RFMP is a polyaromatic compound that contains a phosphate, which can readily chelate with the metal center on the surface of Fe3O4 MNPs. The aromatic rings on RFMP can interact with BP (K-d = similar to 6.73 x 10(-5) M) through pi-pi stacking. Thus, Fe3O4@RFMP MNPs are fabricated by simply mixing Fe3O4 MNPs with RFMP under microwave heating (power: 540 W) for 3 min. The as-prepared Fe3O4@RFMP MNPs can be used as affinity probes to selectively concentrate BP from an acidic solution; BP is then released from the MNPs by using acetonitrile. The recovery of BP from the Fe3O4@RFMP MNP-BP conjugates is estimated to be similar to 100%. This study also demonstrates the feasibility of using the proposed approach to selectively extract BP from complex A. sinensis extract samples.
Susceptor Coupling for the Uniformity and Dopant Activation Efficiency in Implanted Si Under Fixed-Frequency Microwave Anneal
(2012-02-01)
Lee, Yao-Jen
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Hsueh, Fu-Kuo
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Current, Michael I.
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Wu, Ching-Yi
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Chao, Tien-Sheng
Microwave annealing of dopants in Si has been reported to produce highly activated junctions at temperatures far below those needed for comparable results using conventional thermal processes. However, during conventional fixed-frequency microwave heating, standing wave patterns can be established in the microwave processing chamber, resulting in nodes and antinodes over the processing area, resulting in thermal variations over the process wafer. In this letter, the effects of Si or quartz susceptor wafers on dopant activation and sheet resistance uniformity during fixed-frequency microwave anneal are studied. The composition, number, and spacing of susceptor wafers were varied in a systematic fashion in these experiments.