Title: Plasmonic Biosensing with Aluminum Thin Films under the Kretschmann Configuration.

Authors: Lambert, Alexander S; Valiulis, Santino N; Malinick, Alexander S; Tanabe, Ichiro; Cheng, Quan

Published In Anal Chem, (2020 07 07)

Abstract: Aluminum has recently attracted considerable interest as a plasmonic material due to its unique optical properties, but most work has been limited to nanostructures. We report here SPR biosensing with aluminum thin-films using the standard Kretschmann configuration that has previously been dominated by gold films. Electron-beam physical vapor deposition (EBPVD)-prepared Al films oxidize in air to form a nanofilm of Al2O3, yielding robust stability for sensing applications in buffered solutions. FDTD simulations revealed a sharp plasmonic dip in the visible range that enables measurement of both angular shift and reflection intensity change at a fixed angle. Bulk and surface tests indicated that Al films exhibited superb sensitivity performance in both categories. Compared to Au, the Al/Al2O3 layer showed a marked effect of suppressing nonspecific binding from proteins in human serum. Further characterization indicated that Al film demonstrated a higher sensitivity and a wider working range than Au films when used for SPR imaging analysis. Combined with its economic and manufacturing benefits, the Al thin-film has the potential to become a highly advantageous plasmonic substrate to meet a wide range of biosensing needs in SPR configurations.

PubMed ID: 32525300

MeSH Terms: Aluminum Oxide/chemistry; Aluminum/chemistry*; Animals; Biosensing Techniques/methods*; Biotin/chemistry; Blood Proteins/chemistry; Blood Proteins/metabolism; Cattle; Gold/chemistry; Humans; Nanostructures/chemistry; Refractometry; Serum Albumin, Bovine/chemistry; Streptavidin/analysis; Surface Plasmon Resonance/methods