Wide-range quantification of human thyroid-stimulating hormone using gold-nanopatterned single-molecule sandwich immunoassay chip

Plasmonic metal scattering immunoassay by total internal reflection scattering microscopy with nanoscale lateral resolution

“…The protein can be imaged with fluorescentlabeled antibodies using a fluorescence microscope. 18 Although fluorescence imaging enables the quantitative estimation of protein concentration in a sample by fluorescence intensity, it is a time consuming process that is hampered by the photobleaching of fluorescent dyes. To overcome this limitation, several methods of fluorescent-free optical imaging for biomolecules have been reported, including enhanced dark field, 19 differential interference contrast, 20 interferometric measurements, 21 and surface plasmon resonance imaging 22 by nanoparticle labeling.…”

Gold-nanopatterned single interleukin-6 sandwich immunoassay chips with zeptomolar detection capability based on evanescent field-enhanced fluorescence imaging

“…15 Gold nanopatterned chip fabrication using electron beam lithography also showed possible detection at the zM level while manufacturing efficiency and reproducibility were low. 16 In this study, a gold patterned chip with good reproducibility of 100 nm spot diameter was successfully accomplished using electron beam lithography and suggested a possibility for zM detection of IL-6, a kind of cytokine for demonstration of clinical application on this chip.…”

“…13 Although mass spectrometry is currently the technique of choice in sensitivity proteomic investigation because it is capable of detecting single molecules, it has a crude biological sample interface. 14 In our previous reports, 15,16 total internal reection microscopy (TIRFM) system with ultra-high sensitivity had been successfully applied to detect various clinical biomarkers at the zM level. However, the nanopattern on polymer coated glass arrayed by dip-pen nanolithography using atomic force microscopy was not good at the reproducibility of spot shape and inherently limits its shelf-life for use in the longer term.…”

Supersensitive Detection of the Norovirus Immunoplasmon by 3D Total Internal Reflection Scattering Defocus Microscopy with Wavelength-Dependent Transmission Grating

“…In fact, it is not easy to pattern gold nanospots below 100 nm with a uniform size and reproducibility using lithographic techniques (Figure S3a). 35 Issues with patterning have also limited the binding capacity at high concentrations. In addition, background noise increases and sensitivity decreases as the substrate size (gold spot) increases.…”