Developing methods to sense local variations in properties of nearby materials, such as their refractive index and thickness, are important in numerous fields including chemistry and biomedical applications. Localized surface plasmons (LSPs) excited in plasmonic nanostructures have been demonstrated to be useful in this context due to the spectral location of their associated resonances being sensitive to changes in the environment near the plasmonic structures. This manuscript explores Babinet's principle by exploiting LSP resonances excited in complementary metal-dielectric cylindrical plasmonic structures (plasmonic particle-dimers and aperture-dimers in our case). Both plasmonic structures are evaluated numerically and experimentally using electron energy loss spectroscopy (EELS), providing a full physical understanding of the complementary nature of the excited LSP resonances. These plasmonic structures are then exploited for dielectric sensing under two configurations: when a thin dielectric film is positioned atop the plasmonic structures and when the analyte surrounds/fills the plasmonic particles/apertures. The complementary sensing performance of both proposed structures is also evaluated, showing the approximate validity of the Babinet principle with sensitivity values of up to ∼650 nm/RIU for thin dielectric sensing.

• Klíčová slova
• Babinet, dielectric sensing, nanoantennas, nanoparticles, plasmonic dimers, plasmonics,
• Publikační typ
• časopisecké články MeSH

A biosensor for the detection of hepatitis B antibodies in clinical saliva was developed. Compared to conventional analysis of blood serum, it offers the advantage of noninvasive collection of samples. Detection of biomarkers in saliva imposes two major challenges associated with the low analyte concentration and increased surface fouling. The detection of minute amounts of hepatitis B antibodies was performed by plasmonically amplified fluorescence sandwich immunoassay. To have access to specific detection, we prevented the nonspecific adsorption of biomolecules present in saliva by brushes of poly[(N-(2-hydroxypropyl) methacrylamide)-co-(carboxybetaine methacrylamide)] grafted from the gold sensor surface and post modified with hepatitis B surface antigen. Obtained results were validated against the response measured with ELISA at a certified laboratory using serum from the same patients.

• MeSH
• biologické markery analýza   MeSH
• biosenzitivní techniky metody   MeSH
• fluorescenční spektrometrie MeSH
• hepatitida B - antigeny povrchové chemie   imunologie   MeSH
• hepatitida B - protilátky analýza   krev   imunologie   MeSH
• imobilizované proteiny chemie   imunologie   MeSH
• imunoanalýza MeSH
• lidé MeSH
• polymery chemie   MeSH
• povrchová plasmonová rezonance MeSH
• sliny metabolismus   MeSH
• zlato chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické markery MeSH
• hepatitida B - antigeny povrchové MeSH
• hepatitida B - protilátky MeSH
• imobilizované proteiny MeSH
• polymery MeSH
• zlato MeSH