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Two-Dimensional Algal Collection and Assembly by Combining AC-Dielectrophoresis with Fluorescence Detection for Contaminant-Induced Oxidative Stress Sensing.

Siebman C, Velev OD, Slaveykova VI - Biosensors (Basel) (2015)

Bottom Line: An alternative current (AC) dielectrophoretic lab-on-chip setup was evaluated as a rapid tool of capture and assembly of microalga Chlamydomonas reinhardtii in two-dimensional (2D) close-packed arrays.The results showed significant increase of the cellular ROS when C. reinhardtii was exposed to high concentrations of methylmercury, CuO-NPs, and 10⁻⁵ M Cu.Overall, this study demonstrates the potential of combining AC-dielectrophoretically assembled two-dimensional algal structures with cell metabolic analysis using fluorescence staining, as a rapid analytical tool for probing the effect of contaminants in highly impacted environment.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 10 route de Suisse, Versoix CH-1290, Switzerland. coralie.suscillon@unige.ch.

ABSTRACT
An alternative current (AC) dielectrophoretic lab-on-chip setup was evaluated as a rapid tool of capture and assembly of microalga Chlamydomonas reinhardtii in two-dimensional (2D) close-packed arrays. An electric field of 100 V·cm⁻¹, 100 Hz applied for 30 min was found optimal to collect and assemble the algae into single-layer structures of closely packed cells without inducing cellular oxidative stress. Combined with oxidative stress specific staining and fluorescence microscopy detection, the capability of using the 2D whole-cell assembly on-chip to follow the reactive oxygen species (ROS) production and oxidative stress during short-term exposure to several environmental contaminants, including mercury, methylmercury, copper, copper oxide nanoparticles (CuO-NPs), and diuron was explored. The results showed significant increase of the cellular ROS when C. reinhardtii was exposed to high concentrations of methylmercury, CuO-NPs, and 10⁻⁵ M Cu. Overall, this study demonstrates the potential of combining AC-dielectrophoretically assembled two-dimensional algal structures with cell metabolic analysis using fluorescence staining, as a rapid analytical tool for probing the effect of contaminants in highly impacted environment.

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2D-cell array sensing of oxidative stress during short-term exposure to contaminants. (a) Mean corrected CellROX® fluorescent intensity (CF) for different contaminants; Different letters indicate significant differences between means (p < 0.05, Student-Neuman-Keuls test); (b) Fluorescence microscopy of the CellROX® stained cells collected in 2D-assembly by positive DEP in the absence of contaminant (control), presence of 50 mg/L CuO-NPs and 10−7 M diuron; Exposure time of 30 min and 120 min.
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biosensors-05-00319-f006: 2D-cell array sensing of oxidative stress during short-term exposure to contaminants. (a) Mean corrected CellROX® fluorescent intensity (CF) for different contaminants; Different letters indicate significant differences between means (p < 0.05, Student-Neuman-Keuls test); (b) Fluorescence microscopy of the CellROX® stained cells collected in 2D-assembly by positive DEP in the absence of contaminant (control), presence of 50 mg/L CuO-NPs and 10−7 M diuron; Exposure time of 30 min and 120 min.

Mentions: The 2D-assemblies were used to probe the contaminant-induced ROS in C. reinhardtii during short-term exposure of 30 and 120 min (Figure 6a–d). Among the tested contaminants, MeHg induced significant production of ROS at concentrations of 10−9 and 10−7 M where CF values increased from 4.28 ± 0.61 and 4.14 ± 1.18 at 30 min to 4.3 ± 0.56 and 5.03 ± 0.98 at 120 min, respectively. No enhancement of cellular ROS was observed in the presence of 10−8 M of Hg or diuron. 10−7 M Hg however induced a rapid increase on ROS production, as the CF value of the exposed cell layers are two times higher at 30 min compared to unexposed controls. Nevertheless, the ROS production level off with exposition time with CF of 2.94 ± 0.51 at 120 min, comparable with the one for control 2.92 ± 0.46 at 120 min. Significant increase of ROS production was observed with 10 and 50 mg·L−1 of CuO-NPs after 120 min exposure with CF of 3.85 ± 0.73 and 5.72 ± 0.43, respectively.


Two-Dimensional Algal Collection and Assembly by Combining AC-Dielectrophoresis with Fluorescence Detection for Contaminant-Induced Oxidative Stress Sensing.

Siebman C, Velev OD, Slaveykova VI - Biosensors (Basel) (2015)

2D-cell array sensing of oxidative stress during short-term exposure to contaminants. (a) Mean corrected CellROX® fluorescent intensity (CF) for different contaminants; Different letters indicate significant differences between means (p < 0.05, Student-Neuman-Keuls test); (b) Fluorescence microscopy of the CellROX® stained cells collected in 2D-assembly by positive DEP in the absence of contaminant (control), presence of 50 mg/L CuO-NPs and 10−7 M diuron; Exposure time of 30 min and 120 min.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493552&req=5

biosensors-05-00319-f006: 2D-cell array sensing of oxidative stress during short-term exposure to contaminants. (a) Mean corrected CellROX® fluorescent intensity (CF) for different contaminants; Different letters indicate significant differences between means (p < 0.05, Student-Neuman-Keuls test); (b) Fluorescence microscopy of the CellROX® stained cells collected in 2D-assembly by positive DEP in the absence of contaminant (control), presence of 50 mg/L CuO-NPs and 10−7 M diuron; Exposure time of 30 min and 120 min.
Mentions: The 2D-assemblies were used to probe the contaminant-induced ROS in C. reinhardtii during short-term exposure of 30 and 120 min (Figure 6a–d). Among the tested contaminants, MeHg induced significant production of ROS at concentrations of 10−9 and 10−7 M where CF values increased from 4.28 ± 0.61 and 4.14 ± 1.18 at 30 min to 4.3 ± 0.56 and 5.03 ± 0.98 at 120 min, respectively. No enhancement of cellular ROS was observed in the presence of 10−8 M of Hg or diuron. 10−7 M Hg however induced a rapid increase on ROS production, as the CF value of the exposed cell layers are two times higher at 30 min compared to unexposed controls. Nevertheless, the ROS production level off with exposition time with CF of 2.94 ± 0.51 at 120 min, comparable with the one for control 2.92 ± 0.46 at 120 min. Significant increase of ROS production was observed with 10 and 50 mg·L−1 of CuO-NPs after 120 min exposure with CF of 3.85 ± 0.73 and 5.72 ± 0.43, respectively.

Bottom Line: An alternative current (AC) dielectrophoretic lab-on-chip setup was evaluated as a rapid tool of capture and assembly of microalga Chlamydomonas reinhardtii in two-dimensional (2D) close-packed arrays.The results showed significant increase of the cellular ROS when C. reinhardtii was exposed to high concentrations of methylmercury, CuO-NPs, and 10⁻⁵ M Cu.Overall, this study demonstrates the potential of combining AC-dielectrophoretically assembled two-dimensional algal structures with cell metabolic analysis using fluorescence staining, as a rapid analytical tool for probing the effect of contaminants in highly impacted environment.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Science, Faculty of Sciences, University of Geneva, 10 route de Suisse, Versoix CH-1290, Switzerland. coralie.suscillon@unige.ch.

ABSTRACT
An alternative current (AC) dielectrophoretic lab-on-chip setup was evaluated as a rapid tool of capture and assembly of microalga Chlamydomonas reinhardtii in two-dimensional (2D) close-packed arrays. An electric field of 100 V·cm⁻¹, 100 Hz applied for 30 min was found optimal to collect and assemble the algae into single-layer structures of closely packed cells without inducing cellular oxidative stress. Combined with oxidative stress specific staining and fluorescence microscopy detection, the capability of using the 2D whole-cell assembly on-chip to follow the reactive oxygen species (ROS) production and oxidative stress during short-term exposure to several environmental contaminants, including mercury, methylmercury, copper, copper oxide nanoparticles (CuO-NPs), and diuron was explored. The results showed significant increase of the cellular ROS when C. reinhardtii was exposed to high concentrations of methylmercury, CuO-NPs, and 10⁻⁵ M Cu. Overall, this study demonstrates the potential of combining AC-dielectrophoretically assembled two-dimensional algal structures with cell metabolic analysis using fluorescence staining, as a rapid analytical tool for probing the effect of contaminants in highly impacted environment.

Show MeSH
Related in: MedlinePlus