Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7231255 | Biosensors and Bioelectronics | 2016 | 6 Pages |
Abstract
A nanoimmunosensor based on wavelength-dependent dark-field illumination with enhanced sensitivity was used to detect a disease-related protein molecule at zeptomolar (zM) concentrations. The assay platform of 100-nm gold nanospots could be selectively acquired using the wavelength-dependence of enhanced scattering signals from antibody-conjugated plasmonic silver nanoparticles (NPs) with on-off switching using optical filters. Detection of human thyroid-stimulating hormone (hTSH) at a sensitivity of 100Â zM, which corresponds to 1-2 molecules per gold spot, was possible within a linear range of 100Â zM-100Â fM (R=0.9968). A significantly enhanced sensitivity (~4-fold) was achieved with enhanced dark-field illumination compared to using a total internal reflection fluorescence immunosensor. Immunoreactions were confirmed via optical axial-slicing based on the spectral characteristics of two plasmonic NPs. This method of using wavelength-dependent dark-field illumination had an enhanced sensitivity and a wide, linear dynamic range of 100Â zM-100Â fM, and was an effective tool for quantitatively detecting a single molecule on a nanobiochip for molecular diagnostics.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Seungah Lee, He Nan, Hyunung Yu, Seong Ho Kang,