• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.145-152
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• 2008

A cell-based in vitro exposure system was developed to determine whether oxidative stress plays a role in the cytotoxic effects of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and chlorobenzene, using human epithelial HeLa cells. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for immobilization of the HeLa cells on a gold (Au) substrate. In addition, an immobilized cell-based sensor was applied to the electrochemical detection of the VOCs. Layer formation and immobilization of the cells were investigated with surface plasmon resonance (SPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The adhered living cells were exposed to VOCs; this caused a change in the SPR angle and the VOC-specific electrochemical signal. In addition, VOC toxicity was found to correlate with the degree of nitric oxide (NO) generation and EIS. The primary reason for the marked increase in impedance was the change of aqueous electrolyte composition as a result of cell responses. The p53 and NF-${\kappa}B $ downregulation were closely related to the magnitude of growth inhibition associated with increasing concentrations of each VOC. Therefore, the proposed cell immobilization method, using a self-assembly technique and VOC-specific electrochemical signals, can be applied to construct a cell microarray for onsite VOC monitoring.

• KSBB Journal
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• 제17권1호
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• pp.20-25
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• 2002

We performed a basic experiment for rapid, on-line, real-time measurement of HBsAg by using a surface plasmon resonance biosensor to quantify the recognition and interaction of biomolecules. We immobilized the anti-HBsAg polyclonal antibody to the dextran layer on a CM5 chip surface which was pre-activated by N-hydroxysuccinimide for amine coupling. The binding of the HBsAg to the immobilized antibody was measured by the mass increase detected by the change in the SPR signal. The binding characteristics between HBsAg and its antibody followed typical monolayer adsorption isotherm. When the entire immobilized antibody was interacted, there was no additional, non-specific binding observed, which suggested the biointeraction was very specific as expected and independent of the ligand density. No significant steric hindrance was observed at 17.6 nm/$mm^2$ immobilization density. The relationship between the HBsAg concentration in the sample solution and the antigen bound to the chip surface was linear up to ca. $40\mu\textrm{g}$/mL, which is much wider than that of the ELISA method. It appeared the antigen-antibody binding was increased as the immobilized ligand density increased, but verification is warranted. This study showed the potential of this biosensor-based method as a rapid, simple, multi-sample, on-line assay. Once properly validated, it can serve as a more powerful method for HBsAg quantification replacing the current ELISA method.

• KSBB Journal
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• 제28권1호
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• pp.54-59
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• 2013

Three isolates, E. faecium P1, P2 and P3, from intestinal drugs of three phamaceutical companies, four clinical vancomycin resistant isolates, E. faecium V1, V2, V3 and E. faecalis V4, and three isolates, E. faecalis DW01, DW07 and DW14, from infant feces were tested for the presence of virulence genes, ace, agg, esp, efaA, gelE, sprE, vanA and vanB as well as fsrABC, regulatory genes of gelE and sprE, cylMBA, cytolysin activation genes and cpd, cob and ccf, pheromone genes by PCR and for their phenotype activities such as protease, biofilm formation, cell clumping and hemolysis. The genes encoding cell surface adherence proteins, ace, agg, esp and efaA, were predominantly amplified from the vancomycin resistant strain V4 and the fecal isolates DW01, DW07 and DW14. Both protease and biofilm formation activity were detected only from E. faecalis V4 from which the PCR products of gelE and spreE as well as fsrABC were amplified. The pheromone genes were amplified from the V4, DW01, DW07 and DW14 strains and these strains showed clumping activity. Biofilm formation was observed from the strains DW01, DW07 and DW14, all of which produced PCR products of pheromone, and V4 as well. Whole cytolysin regulator genes were amplified from DW01, DW07 and DW14 and ${\beta}$-hemolysis activity was detected from these strains. Any virulence genes or activities except the pheomone gene ccf were not detected from the pharmaceutical isolates, E. faecium P1, P2 and P3.

• 센서학회지
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• 제28권6호
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• pp.355-359
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• 2019

Exosomes, known as nanoscale extracellular vesicles in the range of 30-150 nm, are known to contain clinically significant information. However, there is still insufficient information on exosomal membrane proteins for cancer diagnosis. In this work, we investigated the characteristics of the membrane proteins of exosomes shed by cultured breast cancer cell lines using a surface plasmon resonance (SPR) spectroscopy and pre-activated alkanethiols modified sensor chips. The antibodies of breast cancer biomarkers such as MCU-16, EpCAM, CD24, ErbB2, and CA19-9 were immobilized on the pre-activated alkanethiols surfaces without any activation steps. The purified exosomes were loaded onto each antibody surface. The affinity rank of the antibody surfaces was decided by the relative capture efficiency factors for the exosomes. In addition, an antibody with a relative capture efficiency close to 100% was tested with exosome concentration levels of 10⁴/µl, 10⁵/µl, and 10⁶/µl for quantitative analysis.

• Journal of Preventive Medicine and Public Health
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• 제30권1호
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• pp.103-128
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• 1997

The object of this study is to evaluate the possibility of chemical-induced liver disorder among workers exposed to various chemicals and to classify the the liver function abnormalities by causes and to analyse the risk factors for each liver disorders. A cross-sectional study including questionnaire survey, physical examination, laboratory tests and ultrasonography of liver was conducted on 1,126 workers, 459 workers in a coal chemical plant(company A) and 667 workers in an insulation material manufacturing factory(company B). An industrial hygienist reviewed the chemicals used in both companies and evaluated the work environments to classify the workers by chemical exposure semiquantitatively. The results are as follows: 1. Of 459 workers in company A, 83 workers(18.1%) are classified as nonexposed, group 163(35,5%) as short-term exposure group, 155(33.8%) as intermediately exposed group and 58(12.6%) as long-term exposed group bared on the mean daily exposure to hepatotoxic chemicals evaluated by an industrial hygienist. Of 667 workers in company B, 484(72.6%) workers were classified as nonexposed and 183(35.5%) as exposed group. 2. Workers with SGOT level higher than 40 IU/l were (10.0%) in company A and 77(11.5%) in company 3, and those with SGPT level higher than 35 IU/l were 118(25.7%) in company A and 198(29.7%) in company B. The differences were not significant between companies and between exposure groups(p>0.05). Workers with $\gamma-GT$ level higher than 62 IU/l were 29(6.3%) in company A and 77(11.5%) in company B (p<0.01). The difference between exposure groups was not significant(p>0.05) within companies. Workers with liver function abnormalities(defined as SGOT higher than 40 IU/l or SGPT higher than 35 IU/l) were 338(30.0%) among 1,126 workers. Of 338 workers with live. function abnormalities 139(12.3%) had fatty liver by ultrasonography, 79(7.0%) had alcoholic liver(defined as workers with liver function abnormalities with weekly alcohol consumption greater than 280 g for more than 5 years), 54(4.8%) had hepatitis B, 12(1.1%) had hepatitis C and the other 114(33.7%) was not otherwise classified. Prevalences of alcoholic liver and fatty liver were significantly lower in company A(prevalence ratio 0.24 for alcoholic liver, p<0.001, prevalence ratio 0.76 for fatty liver, p<0.05) but prevalences of liver disorders between exposure groups within companies were not significant(p>0.05). 3. Summary prevalence ratios(SPR) of live. function abnormalities, fatty live. and other liver disorders, adjusted by age and company were not significantly higher in exposed group in any chemicals(p>0.05) but in some chemicals, SPRs were significantly lower. 4. On simple analysis of risk factors for liver function abnormalities, prevalence odds ratio(POR) of those with age between 30 and 39 was 1.54(p<0.01) and those with age ever 40 was 1.51(p<0.01). POR of those with histories of liver disorders and general anesthesia was 1.77(p<0.001) and 4.02 for those with overweight and 6.23 for those with obesity, defined by body mass index(p<0.001). 5. On logistic regression analysis, risk factors of liver function abnormality were fatty liver(POR 2.92 for grade 1, 12.15 for grade 2), presence of hepatitis B surface antigen(POR 3.62) and obesity(POR 5.38 for overweight and 16.52 for obesity). Presence of hepatitis B surface antigen(POR 0.18) was the only preventive facto. of fatty live. Company(POR 0.30) and obesity(POR 2.49 for overweight, 4.52 for obesity) were related to the alcoholic live. Obesity(POR 2.94 for overweight) was the only significant risk factor of hepatitis B and there was no significant risk factor for liver function abnormality not otherwise classified. It is concluded that the evidence of liver disorder related with chemical exposure is not evident in these factories. It is also postulated that fatty liver and alcoholic liver is most common causes of liver function abnormalities among workers and effort for weight control and improvement of life style should be done.