Preliminary results on an innovative plasmonic device for macromolecules analysis and sequencing

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights•New device concept for rapid analysis and sequencing of macromolecules is presented.•We have integrated a plasmonic antenna (PA) with an electrical contact.•We perform FDTD simulations on innovative “Wedding Cake Grating”.•We demonstrate the possibility to couple a SPP generated by the WCG on a PA.•Adiabatic compression and an enhancement until 50 times the field is shown.

In this work we present the fabrication and theoretical simulation for a new device constituted by a on Substrate Plasmonic Antenna (SPA) combined with a bio-functionalized Atomic Force Microscopy (AFM) cantilever. This device could represent a new strategy to sequence and analyze a single protein or DNA. The idea is to use an SPA composed of an innovative “wedding cake” shaped grating (WCG), in order to excite a Surface Plasmon Polariton (SPP) mode, and a 30° tilted Plasmonic Antenna (PA), able to compress adiabatically the SPP until the tip. The Plasmonic device is placed inside an electrical contact that could be used to unfold protein molecules or DNA. A bio-functionalized AFM tip can be used to fish a single biological element and for alignment with the SPA. Then the unfolded element could be scanned close to the PA and a Tip Enhanced Raman Signal (TERS) can be recorded from the biomolecule. The spatial resolution is limited by the size of the radius of curvature of the antenna, which in this work is about 15 nm, while the vertical scanning is controlled by the piezoelectric of the AFM set up. In this work we demonstrate the possibility to fabricate this innovative plasmonic device and we report FDTD simulations of the innovative WCG. The FDTD simulations show the generation of a plasmonic mode that, coupled with the antenna, give rise to an adiabatic compression which produce an increase of the electric field of about 40 times.