Communication Dans Un Congrès Année : 2022

Dual gate organic thin film transistor for biosensing applications

Résumé

Biosensors industry have seen great improvement with the arrival of hybrid microsystems, achieving very low detection limits and high selectivity. Organic electronics, compared to silicon industry, draws a lot of assets for biological analyses : low impact materials, biocompatibility, flexible and stretchable large area substrates [1]. In this study, we investigate the potential of a dual-gate organic thin film transistor (DGOTFT) for biosensing applications. We started from a single gate organic thin film transistor (OTFT) manufactured in the laboratory [2] to act as a transducing part for the biosensor. We added a functionalised surface with biological molecules as selective bioreceptors. This surface is made with conductive polymer PEDOT:PSS, the same material as the gate electrode, and to be functionalised through silanisation and amine-epoxy coupling [3]. We also designed a layer of 30-50nm of Gold for functionalisation through Au-Thiol bond [4]. To detect a variation of the sensitive surface potential due to the recombination between bioreceptors and target [5], we investigate electrical architectures to connect the sensitive surface to the transistor. Prior tests of functionalisation with labelled oligonucleotides have been conducted on single gate OTFTS[2] to make sure the process does not affect the electrical performances. Here we present a double gate architecture (Figure 1.a & b) inspired from G. Li et al [6] : one sensitive gate (SG) on a floating potential, and one control gate (CG). The process enables fine control of the geometrical parameters : channel width (W) is 1000μm, channel length (L) varies from 5μm to 200μm, and organic films thicknesses are in the 200-1000nm range for dielectrics, and 50-80nm for Organic SemiConductor (OSC). In Figure 1.d is shown a DGOTFT that we built (process in Figure 1.c) in the laboratory. To mimic the charge addition due to biomolecules on the surface, we applied a constant voltage on the SG and plotted the Drain Current (ID) against Control Gate Voltage ((Figure 1.e.i. ii.). Results have shown that the threshold voltage (Vt) is efficiently modulated by the sensitive gate polarisation. We demonstrated that our DGTFT can be responsive to a voltage shift (like an artificial biomolecule deposition) on its sensitive gate, with tuneable detection point through polarisation of the control gate. Such results are promising : the large amount of controllable parameters (dimensions, thicknesses) can be optimised through further explorations of the electrical and biological response, this to maximise the sensitivity and performances of the device for biosensing.
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Dates et versions

cea-04662895 , version 1 (26-07-2024)

Identifiants

  • HAL Id : cea-04662895 , version 1

Citer

Thibault Fresneau, Krunoslav Romanjek, Pascal Mailley. Dual gate organic thin film transistor for biosensing applications. XVIIth GFB Conference -, Sep 2022, Saint Dié-des-Vosges, France. ⟨cea-04662895⟩
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