K.V. Sreekanth, Y. Alapan, M. ElKabbash, E. Ilker, M. Hinczewski, U. A. Gurkan, A. De Luca and G. Strangi

1- Department of Physics, CaseWestern Reserve University, 10600 Euclid Avenue, Cleveland, Ohio 44106, USA.
2- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, Ohio 44106, USA.
3- Biomedical Engineering Department, CaseWestern Reserve University, Cleveland, Ohio 44106, USA.
4- Department of Orthopedics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
5- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Aairs Medical Center, Cleveland, Ohio 44106, USA.
6- CNR-NANOTEC Istituto di Nanotecnologia and Department of Physics, University of Calabria, 87036-Rende, Italy.

Abstract

Optical sensor technology offers significant opportunities in the field of medical research and clinical diagnostics, particularly for the detection of small numbers of molecules in highly diluted solutions. Several methods have been developed for this purpose, including label-free plasmonic biosensors based on metamaterials. However, the detection of lower-molecularweight (<500Da) biomolecules in highly diluted solutions is still a challenging issue owing to their lower polarizability. In this context, we have developed a miniaturized plasmonic biosensor platform based on a hyperbolic metamaterial that can support highly confined bulk plasmon guided modes over a broad wavelength range from visible to near infrared. By exciting these modes using a grating-coupling technique, we achieved dierent extreme sensitivity modes with a maximum of 30,000nm per refractive index unit (RIU) and a record figure of merit (FOM) of 590.We report the ability of the metamaterial platform to detect ultralow-molecular-weight (244Da) biomolecules at picomolar concentrations using a standard affnity model streptavidin–biotin.