Ultralow Voltage, OTFT‐Based Sensor for Label‐Free DNA Detection

Lai, Stefano; Demelas, Monia; Casula, Giulia; Cosseddu, Piero; Barbaro, Massimo; Bonfiglio, Annalisa

doi:10.1002/adma.201202996

Cited by 117 publications

(113 citation statements)

References 22 publications

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“…Further, the sensing event can also be introduced at the gate electrode, see Figure 3.6d, as this may change the charge or the effective work function (potential) of the gate, which in turn would influence the charging of the transistor channel [62] . There are also successful approaches where the sensing event has been entirely separated from the transistor channel and instead utilizes charging of a floating gate [63] . In such an approach, the sensor reaction is chemically completely de-coupled from the transistor channel-insulator-gate configuration.…”

Section: Electrolyte Gated Thin Film Transistor Sensorsmentioning

confidence: 99%

Operating Organic Electronics via Aqueous Electric Double Layers

Toss¹

2015

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The field of organic electronics emerged in the 1970s with the discovery of conducting polymers. With the introduction of plastics as conductors and semiconductors came many new possibilities both in production and function of electronic devices. Polymers can often be processed from solution and their softness provides both the possibility of working on flexible substrates, and various advantages in interfacing with other soft materials, e.g. biological samples and specimens. Conducting polymers readily partake in chemical and electrochemical reactions, providing an opportunity to develop new electrochemically driven devices, but also posing new problems for device engineers.The work of this thesis has focused on organic electronic devices in which aqueous electrolytes are an active component, but still operating in conditions where it is desirable to avoid electrochemical reactions. Interfacing with aqueous electrolytes occurs in a wide variety of settings, but we have specifically had biological environments in mind as they necessarily involve the presence of water. The use of liquid electrolytes also provides the opportunity to deliver and change the device electrolyte continuously, e.g. through microfluidic systems, which could then be used as a dynamic feature and/or be used to introduce and change analytes for sensors. Of particular interest is the electric double layer at the interface between the electrolyte and other materials in the device, specifically its sensitivity to charge reorganization and high capacitance.The thesis first focuses on organic field effect transistors gated through aqueous electrolytes. These devices are proposed as biosensors with the transistor architecture providing a direct transduction and amplification so that it can be electrically read out. It is discussed both how to distinguish between the various operating mechanisms in electrolyte thin film transistors and how to choose a strategy to achieve the desired mechanism. Two different strategies to suppress ion penetration into, and thus electrochemical doping of, the organic semiconductor are presented.The second focus of the thesis is on polarization of ferroelectric polymer films through electrolytes. A model for the interaction between the remnant ferroelectric charge in the polymer film and the mobile ionic charges of the electrolyte is presented, and verified experimentally. The reorientation of the ferroelectric polarization via the electric double layer is also demonstrated in a regenerative medicine application; the ferroelectric polarization is shown to affect cell binding, and is used as a gentle method to non-destructively detach cells from a culture substrate. Populärvetenskaplig SammanfattningUpptäckten av ledande polymerer på 1970-talet blev startskottet för forskningsområdet ledande plaster och senare också för organisk elektronik. Möjligheten att använda polymera material, det vill säga plaster, som elektrisk ledare och halvledare i elektroniska komponenter innebär en rad olika fördelar med avseende ...

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Section: Electrolyte Gated Thin Film Transistor Sensorsmentioning

confidence: 99%

Operating Organic Electronics via Aqueous Electric Double Layers

Toss¹

2015

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“…On the other hand, lowering the ionic strength of the measurement solution (after hybridization has occurred) is not advisable as, in these conditions, a denaturation of the hybridized double-strands may occur. 15 In the recent past, we proposed a device structure for DNA hybridization sensing based on floating gate transistors, which can be implemented both in CMOS (Charge-Modulated FET, CMFET 16 ) and organic technology (Organic CMFET, OCMFET 17,18 ). The structure of the OCMFET is based on a floating gate structure; a part of the floating gate, namely, the sensing area, is used for detection in liquid environment without needing of a reference electrode in solution.…”

mentioning

confidence: 99%

“…The structure of the OCMFET is based on a floating gate structure; a part of the floating gate, namely, the sensing area, is used for detection in liquid environment without needing of a reference electrode in solution. 19 In particular, in Lai et al, 18 a new implementation of the device capable to operate at low voltages was presented; such a feature was obtained thanks to an innovative, hybrid organic-inorganic insulating film which can be fabricated with an highly reliable process. 20 The transduction mechanism of the OCMFET is based on the modulation of the floating gate voltage due to the variation of the charge related to biomolecules anchored onto the sensing area.…”

mentioning

confidence: 99%

“…Subsequently, in order to further explore the mechanisms that give rise to the observed sensitivity of the device in hybridization detection, the tests carried out in Ref. 18 were here repeated by modulating the probe length for a fixed Debye length in the measurement buffer. In particular, three probes were employed: P 24 , P 31, and P 42 .…”

mentioning

confidence: 99%

“…The P 31 sequence was the same employed in the original tests reported in Ref. 18; consequently, P 24 and P 42 allow considering a lower and a higher hybridization distance. Hybridization was performed in ambient conditions and at room temperature.…”

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confidence: 99%

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The role of polarization-induced reorientation of DNA strands on organic field-effect transistor-based biosensors sensitivity at high ionic strength

Lai

Barbaro

Bonfiglio

2015

Applied Physics Letters

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The detection of the intrinsic charge of biochemical molecules is a promising strategy for the fabrication of field-effect transistor (FET)-based sensors for direct, non-destructive detection of several biochemical reactions. Nevertheless, the high ionic concentration of standard environments for biochemical species represents a significant limitation to this sensing strategy. Here, an investigation on the physical mechanisms behind the ability of an organic FET-based sensor to detect DNA hybridization at high ionic strengths is proposed. The capability of the device to correctly detect single-stranded DNA oligonucleotides and their hybridization with a complementary target sequence has been analyzed in detail. In particular, the electrical response in solutions with different ionic strengths was investigated and put in relation with the nano-scale properties of DNA strands employed as receptors. Fluorescence analysis shows that it is possible to electrically modify their orientation and consequently improve the device sensitivity in conditions close to those occurring during in vivo hybridization.

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