Browsing by Author "Chang, Hsien-Chang"

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AN AFFINITY SENSOR IMPROVED BY EWOD ACTUATOR-BASED MICROFLUIDIC CHIP
(2009-12-01)
Liu, Chin-Wei
;
Lin, Chi-Chang
;
Chen, Li-Chia
;
Fan, Shih-Kang
;
Chang, Hsien-Chang
We propose an improved immunoassay method with EWOD-based microfluidic biochip. Electro-wetting on dielectric (EWOD) is based on contact angle-changed phenomenon of droplet on the channel surface. The reactant-containing droplet can be moved from reservoir to a modified electrode area, which a stir function can be provided by controlling AC electro-osmosis flow (ACEOF). The immunochemistry reaction takes place on our modified area via electro-wetting actuation, and the signal from fluorescent or electrochemical impedance spectroscopy (EIS) was used to confirm the performance of designed element.
Dielectrophoresis System for Testing Antimicrobial Susceptibility of Gram-Negative Bacteria to beta-Lactam Antibiotics
(2017-04-18)
Su, I-Hsiu
;
Ko, Wen-Chien
;
Shih, Chung-Hsin
;
Yeh, Fang-Hao
;
Sun, Yung-Nien
Gram-negative bacteria (GNBs) are common pathogens causing severe sepsis. Rapid evaluation of drug susceptibility would guide effective antibiotic treatment and promote life-saving. A total of 78 Clinical isolates of 13 Gram-negative species collected between April 2013 and November 2013 from two medical centers in Tainan were tested. Bacterial morphology changes in different concentrations of antibiotics were observed under the electric field of a. quadruple electrode array using light microscopy. The minimal inhibitory concentrations (MICs) of four antimicrobial agents, namely, cefazolin, ceftazidime, cefepime, and doripenem, were determined by the dielectrophoretic antimicrobial susceptibility testing (dAST) and by the conventional broth dilution testing (BDT). The antibiotics at the concentration of 1x MIC induced obvious morphological changes in susceptible GNBs, including cell elongation, cell swelling, or lysis, at 90 min. In contrast, resistant strains remained unchanged. The MIC results measured by dAST were in good agreement with those of BDT (essential agreement 95.6%). The Category agreement rate was 89.2%, and the very major errors rate for dAST was 2.9%. In conclusion, dAST could accurately determine drug susceptibility within 90 min. Comprehensive tests by dAST for more drugs against more GNB species are possible in the future.
The photothermal effect of silica-carbon hollow sphere-concanavalin A on liver cancer cells
(2015-01-01)
Chen, Ying-Chi
;
Chiu, Wen-Tai
;
Chen, Jung-Chih
;
Chang, Chia-Sheng
;
Wang, Lily Hui-Ching
Hepatocellular carcinoma (HCC) is one of the most common cancers and causes of death by cancer. Concanavalin A (ConA) lectin can specifically bind to the glycoprotein receptors of HCC, which are produced by the aberrant overexpression of liver cancer cells. ConA was used in the current study to conjugate on silica-carbon hollow spheres (SCHSs) and applied in the thermal ablation therapy of liver cancer cell lines under near-infrared (NIR) laser irradiation. We found that the amount of ConA-SCHS complex binding to hepatoma cells was significantly higher than that seen with normal hepatocytes, based on flow cytometric analysis and confocal imaging. Hepatoma cells incubated with ConA-SCHSs were thus more easily killed by the subsequent irradiation with a NIR laser. The results show that the ConA-SCHS complex may enhance the interaction with highly expressed ConA receptors on hepatoma cells, and thus serve as an effective photothermal therapy agent for liver cancer treatment.