Grantee Research Project Results
2006 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, 2006 through March 31, 2007
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 single molecules, these nanosensors are also attractive due to their 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 proposed 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 rotavirus.
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, in prefabricated channels of tailor-made aspect ratio between two contact electrodes at site-specific positions. In this way, we synthesized biomolecule-functionalized nanowires of tailor-made properties for fabricating individually addressable high-density nanowire biosensor arrays and the successful detection of the target analyte by the detection of resistance/conductance change in chemoresistive mode. Subsequently, we demonstrated facile tunability of the nanowires’ conductivity through the control of its dopant level by controlling the gate potential. The goal of this year was to investigate different methods for biological functionalization of nanowires. Earlier, we had demonstrated incorporation of biomolecules by entrapment during electrochemical polymerization. As an alternative, during the past year, we investigated using a functional monomer that has groups for biomolecule attachment and chemical activation of the amine group in the polyaniline and polypyrrole.
Nitriloacetic acid (NTA), a chelator that chelates heavy metals, such as nickel and copper, is widely used in biological sciences for purification and immobilization of proteins with a histidine tag. We have synthesized an NTA-modified pyrrole monomer, which then was electropolymerized to form 200-nm diameter by 30- to 40-μm long poly(pyrrole)-NTA (PPy-NTA) nanowires using alumina template. The PPy-NTA nanowires were then converted to a device and applied for detection of heavy metal at the femtomolar/ppt level and the metal-chelated nanowires were shown to detect hexa-histidine-tagged syntaxin protein through the metal-histidine conjugation.
A facile method of functionalizing poly(aniline) and poly(pyrrole) with biomolecules is through a glutaraldehyde linker for functionalization. We have used this simple technique for biofunctionalization of poly(pyrrole) nanowires with anti-bovine serum albumin and applied the antibody-functionalized nanowires to chemoresistive detection of bovine serum albumin.
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 on fabricating antibody-functionalized conducting-polymer nanowires and demonstrating 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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Hernandez SC, Chaudhuri D, Chen W, Myung NV, Mulchandani A. Single polypyrrole nanowire ammonia gas sensor. Electroanalysis 2007;19(19-20):2125-2130. |
GR832375 (2006) |
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Ramanathan K, Bangar MA, Yun M, Chen W, Mulchandani A, Myung NV. In situ fabrication of single poly(methyl pyrrole) nanowire. Electroanalysis 2007;19(7-8):793-797. |
GR832375 (2006) GR832375 (2007) |
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Supplemental Keywords:
nanosensors, viruses, bacteria, monitoring, water,, Sustainable Industry/Business, RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Water, POLLUTANTS/TOXICS, Chemical Engineering, Environmental Chemistry, Engineering, Chemistry, & Physics, Monitoring/Modeling, New/Innovative technologies, Environmental Engineering, Environmental Monitoring, Water Pollutants, electrochemical polymerization, homeland security, environmental measurement, carbon nanotubes, nanowires, nanoengineering, nanotechnology, nanosensors, analytical chemistry, continous monitoring, microbial pathogens, continuous monitoring, nanocontact sensor, immunosensor arrays, bioterrorismProgress 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.