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Proceedings Paper

Label-free detection of antigens using implantable SERS nanosensors
Author(s): Honggang Li; Caitlin E. Baum; Brian M. Cullum
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Paper Abstract

Monitoring the presence, production and transport of proteins inside individual living cells can provide vital information about cellular signaling pathways and the overall biological response of an organism. For example, cellular response to external stimuli, such as biological warfare (BW) agents, can be monitored by measuring interleukin-II (IL-2) expression inside T-cells as well as other chemical species associated with T-cell activation. By monitoring such species, pre-symptomatic detection of exposure to BW agents can be achieved, leading to significantly increased post-exposure survival rates. To accomplish such monitoring, we have developed and optimized implantable nanosphere-based nanosensors for the intracellular analysis of specific proteins in a label-free fashion. These sensors consist of 300-520 nm diameter silica spheres that have been coated with silver and antibodies to allow for trace protein detection via surface enhanced Raman spectroscopy (SERS). They have been optimized for SERS response by evaluating the size of the nanospheres best suited to 632.8 nm laser excitation, as well as the various nanosensor fabrication steps (i.e., silver deposition process, antibody binding, etc.). During usage, the presence of the specific protein of interest is monitored by either directly measuring SERS signals associated with the protein and/or changes in the SERS spectrum of the antibodies resulting from conformational changes after antigen binding. In this work, human insulin was used as a model compound for initial studies into the sensitivity of these optimized nanosensors.

Paper Details

Date Published: 11 November 2005
PDF: 12 pages
Proc. SPIE 6007, Smart Medical and Biomedical Sensor Technology III, 60070D (11 November 2005); doi: 10.1117/12.629205
Show Author Affiliations
Honggang Li, Univ. of Maryland/Baltimore County (United States)
Caitlin E. Baum, Univ. of Maryland/Baltimore County (United States)
Brian M. Cullum, Univ. of Maryland/Baltimore County (United States)


Published in SPIE Proceedings Vol. 6007:
Smart Medical and Biomedical Sensor Technology III
Brian M. Cullum; J. Chance Carter, Editor(s)

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