Grantee Research Project Results
1997 Progress Report: Development of a New Microelectrode Array Biosensing System for Environmental Monitoring
EPA Grant Number: R825323Title: Development of a New Microelectrode Array Biosensing System for Environmental Monitoring
Investigators: Sadik, Omowunmi
Institution: The State University of New York at Binghamton
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1996 through September 30, 1999 (Extended to September 30, 2000)
Project Period Covered by this Report: October 1, 1996 through September 30, 1997
Project Amount: $280,095
RFA: Analytical and Monitoring Methods (1996) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Air , Ecological Indicators/Assessment/Restoration , Environmental Statistics
Objective:
Numerous environmental and industrial activities such as bioremediation, human exposure assessment, groundwater monitoring, monitoring agricultural run-offs and detection of early warning signals would benefit from the rapid information provided by label-free, multianalyte chemical and biosensors. Ideally, such sensors should be small, provide fast response times, be reversible and be capable of continuous measurements and be suitable for integration into other devices that allows quick remedial actions to be taken. Although simple in operation, a successful, direct, multianalyte sensor is difficult to develop. The problems involved include the difficulties encountered in microfabrication, bioreagent stability, and efficient generation of analyte signals resulting in incomplete or impossible regeneration of sensing surfaces.At the State University of New York at Binghamton, we are developing this type of new, tunable, multianalyte sensing technologies. The overall goal of the project is to develop, and carry out field demonstration of such multianalyte biosensors for environmental analysis, using conducting polymer electrode arrays and individually addressable sensing chips. This concept of multi-use, multianalyte biosensors with no labels and reversible binding has been used to develop new sensors and to correlate experimentally observed sensor response for several classes of toxic pollutants with absolute concentration levels that can be related to possible sources. This study includes the development of new sensing chemistries based on azo-dye metal protein conjugates, optimization of instrumental variables, developments of models based on study results, and field testing of the concept developed.
Selected priority chemicals studied include Polychlorinated biphenyls, (PCBs), volatile and semi-volatile chlorinated phenols, triazines, polyaromatic hydrocarbons (PAHs) and heavy metals. The techniques utilize a sensing model consisting of polymer modified electrodes, new sensing chemistries based on azo dye protein conjugates, and pattern recognition techniques. The theoretical framework used in describing the sensor response was reported for a simplified phenolic and hapten-antihapten interactions [1-5]. The response for several analytes was studied, and the results expressed as IC50 (i.e. 50% dose response) values for a range of analytes. The combination of sensor arrays and pattern recognition resulted in a rapid method for the identification and quantitation (IQ) of 2,4-D, 2,4,5 TCP, pentachlorophenol and other organics. The limits of detection (LODs) obtained for 2,4,6-TCP, 2-CP and 2,4-D using a 32-array polymer sensors were 0.1, 0.25 and 0.36 ng/mL respectively. The linear dynamic range of the biosensor was between 0.3-100 ng/mL with a correlation coefficient of 0.997 for Aroclor 1242. The LODs for Aroclors 1242, 1248, 1254 and 1016 were 3.3, 1.56, 0.39, and 1.66 ng/mL respectively, and at a signal-to-noise (S/N) ratio of 3. The immunosensor exhibited high selectivity for PCBs in the presence of potential interference such as chlorinated anisoles, benzenes and phenols. The highest cross-reactivity measured for chlorinated phenolic compounds relative to Aroclor 1248 was less than 3%. The recoveries of spiked Aroclors 1242 and 1254 from industrial effluent water, rolling mill and seafood plant pretreated water at 0.5 and 50 ng/mL ranged from 103-106%.
The correlation between the IQ levels of bound analytes and the binding capacities was determined by poising the potential to a positive value in order to measure the interactions. Reversing the applied potential to a more negative value resulted in a regenerated surface of the modified electrodes. Using this routine, the specifically bound analyte molecules are released within minutes and washed out for the next round of interactions. This approach is currently being used to determine a range of quantitative, sensor-activity relationships to be used in predicting sensor behaviors in unknown or complex samples. We are also working on the transfer of this technology onto microelectrode arrays; individually addressable microelectrode sensing chips and field testing of the mutianalyte-sensing concept already developed. This project has been developed with funding from the US-EPA under Grant number R825323.
Journal Articles on this Report : 3 Displayed | Download in RIS Format
Other project views: | All 70 publications | 9 publications in selected types | All 9 journal articles |
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Bender S, Sadik OA. Direct electrochemical immunosensor for polychlorinated biphenyls. Environmental Science & Technology 1998;32(6):788-797. |
R825323 (1997) R825323 (1998) R825323 (1999) R825324 (Final) |
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Masila M, Sargent A, Sadik OA. Pattern recognition studies of halogenated organic compounds using conducting polymer sensor arrays. Electroanalysis 1998;10(5):312-320. |
R825323 (1997) R825323 (1998) R825323 (1999) |
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Sargent A, Sadik OA. Pulsed electrochemical technique for monitoring antibody-antigen reactions at interfaces. Analytica Chimica Acta 1998;376(1):125-131. |
R825323 (1997) R825323 (1998) R825323 (1999) |
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Supplemental Keywords:
Innovative technologies, Environmental contamination, Performance-based Methods, Multianalyte detectors & systems, Rapid Identification and Quantitation Techniques, Continuous monitoring., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Physics, Chemistry, Monitoring/Modeling, Electron Microscopy, Engineering, environmental monitoring, environmental measurement, field portable monitoring, microelectrode, biomonitoring, biosensing system, environmental engineering, spectroscopic, electrochemical analysis, solid waste, groundwaterRelevant Websites:
http://chemiris.chem.binghamton.edu/SADIK/sadik.htmProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.