Grantee Research Project Results
2005 Progress Report: Conducting-Polymer Nanowire Immunosensor Arrays for Microbial Pathogens
EPA Grant Number: GR832375Title: Conducting-Polymer Nanowire Immunosensor Arrays for Microbial Pathogens
Investigators: Mulchandani, Ashok , Yates, Marylynn V. , Myung, Nosang V. , Chen, Wilfred
Current Investigators: Mulchandani, Ashok , Chen, Wilfred , Yates, Marylynn V. , Myung, Nosang V.
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Project Period: June 1, 2005 through March 31, 2008 (Extended to March 31, 2009)
Project Period Covered by this Report: June 1, 2005 through March 31, 2006
Project Amount: $320,000
RFA: Greater Research Opportunities: Research in Nanoscale Science Engineering and Technology (2004) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
Objective:
A promising approach for the direct (label-free) electrical detection of biological macromolecules uses one-dimensional (1-D) nanostructures such as nanowires and nanotubes, configured as field-effect transistors that change conductance upon binding of charged macromolecules to receptors linked to the device surfaces. Combined with simple, rapid, and label-free detection, potentially to a single molecule, these nanosensors are also attractive due to the small size, low power requirement, and most of all the possibility of developing high-density arrays for simultaneous analyses of multiple species. Although current nanosensors based on carbon nanotubes and silicon nanowires have elucidated the power of 1-D nanostructures as biosensors, they have low throughput and limited controllability and are unattractive for fabrication of high-density sensor arrays. More importantly, surface modifications, typically required to incorporate specific antibodies, have to be performed post-synthesis and post-assembly, limiting our ability to individually address each nanostructured sensing element with the desired specificity.
The overall objective of the research is to develop a novel technique for the facile fabrication of bioreceptor (antibody)-functionalized nanowires that are individually addressable and scalable to high-density biosensor arrays and to demonstrate its application for label-free, real-time, rapid, sensitive, and cost-effective detection of multiple pathogens in water. Electropolymerization of conducting polymers between two contact electrodes is a versatile method for fabricating nanowire biosensor arrays with the required controllability. The benign conditions of electropolymerization enable the sequential deposition of conducting-polymer nanowires with embedded antibodies onto a patterned electrode platform, providing a revolutionary route to create "truly" high-density and individually addressable nanowire biosensor arrays. The nanowire immunosensor arrays will be used to simultaneously quantify three important model pathogens: poliovirus, hepatitis A virus, and rotarvirus.
Progress Summary:
Previously, we had demonstrated a simple yet powerful facile technique of electrochemical polymerization of biomolecule-friendly conducting polymers, such as polypyrrole and polyaniline. Biomolecules-functionalized nanowires of tailor-made properties were synthesized in prefabricated channels of tailor-made aspect ratio between two contact electrodes at site-specific positions for fabricating individually addressable high-density nanowire biosensor arrays. Label-free detection of target analyte was achieved by the measuring resistance/conductance change in chemoresistive mode. In order to further improve the detection sensitivity, we have used the single nanowires in a field-effect transistor mode in which the oxidation state (i.e. the conductivity) of the nanowires is tuned by varying the gate potential. A large modulation in the electrical conductivity of up to three orders of magnitude was demonstrated as a result of varying the electrochemical gate potential of these nanowires. Single nanowire conducting polymer field-effect transistors show higher electrical performance than field-effect transistors based on conducting polymer nanowire electrode junctions and thin films in terms of their transconductance (gm) and on/off current (Ion/Ioff) ratio. Furthermore, the performance of single nanowire conducting polymer field-effect transistors was found to be comparable to the silicon nanowire field-effect transistors. These results imply that it is possible to tune the sensitivities of these conducting polymer nanowires by simple control of the electrolyte/liquid ion gate potentials. Based on these findings, we demonstrated the ability to tailor the sensitivities of sensors based on single conducting polymer nanowires.
The investigators working on the project have made several oral and poster presentations at national and international meetings and universities in the United States and abroad.
Future Activities:
In the coming year, research will be performed to: (1) investigate the best route for the incorporation/immobilization of antibodies/bioreceptors onto conducting polymer nanowires; and (2) fabricate antibody-functionalized conducting polymer nanowires and demonstrate their applications for detection of corresponding target analytes.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 9 publications | 9 publications in selected types | All 7 journal articles |
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Type | Citation | ||
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Wanekaya AK, Lei Y, Bekyarova E, Chen W, Haddon R, Mulchandani A, Myung NV. Fabrication and properties of conducting polypyrrole/SWNT-PABS composite films and nanotubes. Electroanalysis 2006;18(11):1047-1054. |
GR832375 (2005) GR832375 (2007) |
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Wanekaya AK, Chen W, Myung NV, Mulchandani A. Nanowire-based electrochemical biosensors. Electroanalysis 2006;18(6):533-550. |
GR832375 (2005) GR832375 (2007) |
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Supplemental Keywords:
nanosensors, viruses, bacteria, monitoring, water,, RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, POLLUTANTS/TOXICS, Sustainable Industry/Business, Chemical Engineering, Environmental Chemistry, Monitoring/Modeling, Environmental Monitoring, New/Innovative technologies, Water Pollutants, Engineering, Chemistry, & Physics, Environmental Engineering, nanosensors, continous monitoring, homeland security, nanowires, environmental measurement, immunosensor arrays, bioterrorism, continuous monitoring, nanotechnology, carbon nanotubes, microchip assays, microbial pathogens, electrochemical polymerization, analytical chemistry, nanocontact sensorProgress 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.