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Title: A resettable in-line particle concentrator using AC electrokinetics for distributed monitoring of microalgae in source waters

Green algae have been studied as an important and effective biomarker to indicate water quality due to their sensitivity to toxic agents in freshwater sources. But, conventional methods to monitor algal physiology use a chlorophyll fluorometer whose use is hampered by high-cost, large footprint, and limited sensitivity for practical samples containing low algal concentration. In order to overcome these constraints, we developed a multi-level electrode platform for resettable trapping of algae via AC electro-osmosis (ACEO) and negative dielectrophoresis. Preliminary experiments were performed in freshwater with conductivity of 0.02 S/m. Algal trapping was demonstrated at a low voltage of 2 V. The concentration effect was experimentally verified by measuring the fluorescence intensity of algae and using hemocytometer counting chambers at the inlet and outlet of the multilevel microchannel lab-on-a-chip. An optimal frequency was found for trapping, which agrees with the frequency dependence of ACEO flow velocity. Through-flow rate and electrode dimensions were optimized as well. Trapping efficiencies within the range of 26% - 65% have been obtained. A maximum trapping rate of 182 cells/s was obtained with a flow rate of 20 l/min. Our lab-on-a-chip shows high potential for improving the limit of detection in algal monitoring and enabling the developmentmore » of a portable, integrated and automated system for monitoring the quality of source drinking waters.« less
 [1] ;  [2] ;  [1] ;  [3] ;  [3]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Electrical Engineering and Computer Science
  2. (United States). Weldon School of Biomedical Engineering
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Sensors and Actuators. B, Chemical
Additional Journal Information:
Journal Volume: 244; Journal Issue: C; Journal ID: ISSN 0925-4005
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 30 DIRECT ENERGY CONVERSION; Microfluidics; AC electrokinetics; in line particle trapping; microalgae; biosensors; source water monitoring
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1417103