CAREER: Reference Compensation for Localized Surface-Plasmon Resonance Sensors

Grants and Contracts Details

Description

Nanoscale metallic structures supporting localized optical surface-plasmon resonances (SPR) have been extensively investigated for label free detection and analysis of biological and chemical interactions. When compared to traditional SPR sensors based on propagating surface plasmon waves, localized SPR sensors offer greater electric field enhancement, sensing in dramatically reduced solution volumes, and extensive tunability based on size, shape, material, and dielectric environment. Despite these advantages, two major challenges remain before localized SPR sensors will be appropriate for field deployment in environmental monitoring, food safety, point-of-delivery medical care, and defense and security applications. (1) Localized SPR sensors remain highly susceptible to interference because they respond to both solution refractive index changes and non-specific binding as well as specific binding of the target analyte. Therefore, reference compensation is essential for use of SPR sensors outside the laboratory. (2) Little is known about how to interrogate localized SPR sensors using integrated optical systems. Nevertheless, such interrogation systems are necessary to develop manufacturable sensor platforms for high-density arrays or in-vivo use. To address these challenges the proposed research effort will develop localized SPR sensors that use multiple surface-plasmon resonances to distinguish target analytes from non-specific effects. In addition, the proposed work will investigate how to interrogate such sensors using integrated optical waveguides. The integrated educational plan uses nanoscale photonic sensors as an educational platform for undergraduate and graduate level training and as an outreach mechanism to attract underrepresented Appalachian students to careers in engineering and science. First, the proposed effort seeks to understand how to design novel metallic nanostructures that support multiple surface-plasmon modes with strongly differentiated electric field profiles. This characteristic allows specific and non-specific interactions, which occur at different locations on the sensor, to be distinguished. The second research objective is to fabricate and characterize optimized sensors that provide reference compensation when used in complex media. Approaches based on the assembly of chemically synthesized nanostructures and on direct fabrication via electron-beam lithography will be investigated. Third, integrated optical waveguides will be developed that allow strong interaction between guided modes and the metallic nanostructures for lab-on-a-chip and in-vivo applications. The development of these nanoscale sensors and sensing systems will augment the P.L's development of a new course, NanoPhotonics. This course is uniquely designed to be accessible to electrical, chemical, materials, and mechanical engineering majors at the advanced undergraduate/introductory graduate level. Finally, the P.L will use localized SPR sensors as a demonstration platform for outreach efforts to promising but underrepresented Appalachian high school students in U.K.'s Robinson Scholars program and Kentucky's Rogers' scholar program. The intellectual merit of the proposed research rests on the first use of multiple localized surface-plasmon modes to differentiate the presence of a target analyte from non-specific effects. This effort will not only result in dramatically improved sensor performance, but will also enhance understanding of how to engineer the optical properties of metallic nanostructures. Combining this novel reference compensation approach with an integrated optical interrogation system will provide a platform for the widespread implementation of localized SPR sensors and will also enhance understanding of the interaction of metallic nanostructures with micro-scale dielectric waveguides. The project's broader impact begins with developing a new sensor platform that may better serve society's needs in drug discovery, medical diagnosis, food quality assurance, and bio-chemical defense. From an educational perspective, the project will provide undergraduate and graduate training in an inherently interdisciplinary field by incorporating aspects of electromagnetics, micro- and nano- scale fabrication, chemical sensing, and signal processing. The project will also contribute to the educational infrastructure required to attract and train future engineers through the development of an interdisciplinary NanoPhotonics course, further development of the University of Kentucky's Nanoscale Engineering Certificate Program (NECP), and enhancement of outreach efforts to underrepresented Appalachian students.
StatusFinished
Effective start/end date5/1/084/30/14

Funding

  • National Science Foundation: $400,000.00

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