Label-Free Plasmonic Detection of Biomolecular Binding by a Single Gold Nanorod

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• 作者：Greg J. Nusz ; Stella M. Marinakos ; Adam C. Curry ; Andreas Dahlin ; Fredrik H&ouml ; &ouml ; k ; Adam Wax ; Ashutosh Chilkoti
• 刊名：Analytical Chemistry
• 出版年：2008
• 出版时间：February 15, 2008
• 年：2008
• 卷：80
• 期：4
• 页码：984 - 989
• 全文大小：224K
• 年卷期：v.80,no.4(February 15, 2008)
• ISSN：1520-6882

文摘

We report the use of individual gold nanorods as plasmonic transducers to detect the binding of streptavidinto individual biotin-conjugated nanorods in real time ona surface. Label-free detection at the single-nanorod levelwas performed by tracking the wavelength shift of thenanorod-localized surface plasmon resonant scatteringspectrum using a dark-field microspectroscopy system.The lowest streptavidin concentration that was experimentally measured was 1 nM, which is a factor of 1000-fold lower than the previously reported detection limit forstreptavidin binding by biotinylated single plasmonicnanostructures. We believe that the current optical setupis able to reliably measure wavelength shifts as small as0.3 nm. Binding of streptavidin at 1 nM concentrationinduces a mean resonant wavelength shift of 0.59 nmsuggesting that we are currently operating at close to thelimit of detection of the system.