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Extended Work Function Shift of Large‐Area Biofunctionalized Surfaces Triggered by a Few Single‐Molecule Affinity Binding Events

Authors :
Cinzia Di Franco
Eleonora Macchia
Lucia Sarcina
Nicoletta Ditaranto
Aniqa Khaliq
Luisa Torsi
Gaetano Scamarcio
Source :
Advanced Materials Interfaces, Vol 10, Iss 6, Pp n/a-n/a (2023)
Publication Year :
2023
Publisher :
Wiley-VCH, 2023.

Abstract

Abstract Few binding events are here shown to elicit an extended work function change in a large‐area Au‐surface biofunctionalized with ≈108 capturing antibodies. This is demonstrated by Kelvin probe force microscopy (KPFM), imaging a ≈105 µm2 wide Au‐electrodes covered by a dense layer (≈104 µm−2) of physisorbed anti‐immunoglobulin‐M (anti‐IgM). A 10 min incubation in 100 µL phosphate buffer saline solution encompassing ≈10 IgM antigens (10−19 mole L−1  102 × 10−21 m) produces a work function shift ΔW ≈ –60 meV. KPFM images prove that this shift involves the whole inspected area. Notably, no work function change occurs upon incubation in highly concentrated (3 × 10−15 m) nonbinding IgG solutions. The ΔW measured by KPFM is in quantitative agreement with the threshold voltage shift of an electrolyte‐gated single‐molecule large‐area transistor (SiMoT). The findings provide direct experimental evidence for the SiMoT ultrahigh sensitivity, by imaging the extensive shift of the gate work function, likely arising from collective surface phenomena, elicited by single‐molecule binding events.

Details

Language :
English
ISSN :
21967350
Volume :
10
Issue :
6
Database :
Directory of Open Access Journals
Journal :
Advanced Materials Interfaces
Publication Type :
Academic Journal
Accession number :
edsdoj.29a4831614158907b5da838b886a0
Document Type :
article
Full Text :
https://doi.org/10.1002/admi.202201829