Saturday, October 13, 2012: 8:40 AM
Hall 4E/F (WSCC)
Novel laser wave-mixing spectroscopy is presented as a highly sensitive absorption-based
detection method for biomedical applications including early diagnosis of viral infections. We
are developing laser wave mixing as a sensitive detector for P24 antigen as an alternative for
PCR-based testing used to diagnose HIV and monitor viral loads. P24 is an excellent biomarker
since it reaches readily detectable levels in the host after infection and it has been used to
estimate viral loads in biological samples despite the sensitivity limitations of currently available
assays. Wave mixing offers inherent advantages including excellent sensitivity, small sample
requirements, short optical path length, high spatial resolution and excellent standoff detection
capability. The wave-mixing signal is a coherent laser-like beam and can be collected with
virtually 100% efficiency and minimal background noise. The signal has a quadratic dependence
on analyte concentration, and hence, it yields large signal changes for small changes in chemical
properties. Capillary electrophoresis is used to separate and identify the peptides or biomarkers.
Wave mixing yields excellent detection sensitivity levels even when using thin analytes.
Therefore, wave-mixing is inherently suitable for interfacing microfluidics, microarrays and
capillary electrophoresis separation systems to enhance the chemical specificity levels. Potential
applications include early disease diagnosis and sensitive detection of biomarkers and chem/bio
agents.
Acknowledgments: We gratefully acknowledge NIH NIGMS SDSU IMSD 2R25GM058906-13
(Sashary Ramos), National Institutes of Health (R01), National Science Foundation, U.S.
Department of Defense and U.S. Department of Homeland Security.
Discipline: Chemical Sciences, Analytical/Physical Chemistry, Biochemistry
Keywords: HIV, p24, laser analysis, microfluidics, electrophoresis
detection method for biomedical applications including early diagnosis of viral infections. We
are developing laser wave mixing as a sensitive detector for P24 antigen as an alternative for
PCR-based testing used to diagnose HIV and monitor viral loads. P24 is an excellent biomarker
since it reaches readily detectable levels in the host after infection and it has been used to
estimate viral loads in biological samples despite the sensitivity limitations of currently available
assays. Wave mixing offers inherent advantages including excellent sensitivity, small sample
requirements, short optical path length, high spatial resolution and excellent standoff detection
capability. The wave-mixing signal is a coherent laser-like beam and can be collected with
virtually 100% efficiency and minimal background noise. The signal has a quadratic dependence
on analyte concentration, and hence, it yields large signal changes for small changes in chemical
properties. Capillary electrophoresis is used to separate and identify the peptides or biomarkers.
Wave mixing yields excellent detection sensitivity levels even when using thin analytes.
Therefore, wave-mixing is inherently suitable for interfacing microfluidics, microarrays and
capillary electrophoresis separation systems to enhance the chemical specificity levels. Potential
applications include early disease diagnosis and sensitive detection of biomarkers and chem/bio
agents.
Acknowledgments: We gratefully acknowledge NIH NIGMS SDSU IMSD 2R25GM058906-13
(Sashary Ramos), National Institutes of Health (R01), National Science Foundation, U.S.
Department of Defense and U.S. Department of Homeland Security.
Discipline: Chemical Sciences, Analytical/Physical Chemistry, Biochemistry
Keywords: HIV, p24, laser analysis, microfluidics, electrophoresis