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. © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.

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

Di Franco, C.;Torsi, L.;Scamarcio, G.
2023

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. © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.
2023
Istituto di fotonica e nanotecnologie - IFN - Sede Secondaria Bari
atomic force microscopy, biofunctionalized surfaces, electrolyte gated transistors, Kelvin probe force microscopy, surface potential imaging single-molecule sensors
File in questo prodotto:
File Dimensione Formato  
Adv Materials Inter - 2022 - Di Franco - Extended Work Function Shift of Large‐Area Biofunctionalized Surfaces Triggered by (4).pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 2.13 MB
Formato Adobe PDF
2.13 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/489604
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact