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Organic Electrochemical Transistors Integrated in Flexible Microfluidic Systems and Used for Label-Free DNA Sensing

Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hong Kong, China.
Advanced Materials (Impact Factor: 17.49). 09/2011; 23(35):4035-40. DOI: 10.1002/adma.201102017
Source: PubMed

ABSTRACT

Organic electrochemical transistors are integrated in flexible microfluidic systems. A novel label-free DNA sensor is developed based on devices with single-stranded DNA probes immobilized on gate electrodes. These devices successfully detect complementary DNA targets at low concentrations using a pulse-enhanced hybridization technique in microfluidic channels. Organic electrochemical transistors are excellent candidates for flexible, highly sensitive, and low-cost biosensors.

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    • "Within the family of OTFT-based sensors, organic electrochemical transistors (OECTs) have attracted particular interest [3] [4] [5] [6]. To date, OECTs have been successfully used in sensing different species of analysts, including pH [7], bacteria [8], ions [9], glucose [2] [10] [11], dopamine [12], DNA [13], lactate [14], proteins [15] and cells [16]. "
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    ABSTRACT: Room temperature chemoresistive gas sensors could significantly decrease the demand of power consumption and are thus highly desirable in self-sustained nanosensors. Here we report that chemoresistive sensors fabricated from mesoporous hollow TiO2 microspheres show high sensitivity and selectivity to sub-ppm level of formaldehyde at room temperature with the assistance of low powered UV LED photon energy (2.5 mW). The sensor indicated excellent selectivity to other possible interferrents such as methanol, ethanol, acetone, ammonia and methylbenzene at low concentrations. These sensors have a much faster response (∼40 s)/recovery (∼50 s) characteristic, which significantly surpass the sensing properties shown by other types of nanostructured TiO2 reported in literature.
    Full-text · Article · Nov 2015 · Sensors and Actuators B Chemical
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    • "Within the family of OTFT-based sensors, organic electrochemical transistors (OECTs) have attracted particular interest [3] [4] [5] [6]. To date, OECTs have been successfully used in sensing different species of analysts, including pH [7], bacteria [8], ions [9], glucose [2] [10] [11], dopamine [12], DNA [13], lactate [14], proteins [15] and cells [16]. "
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    ABSTRACT: In organic electrochemical transistor (OECT) based glucose sensors Pt-based electrodes are usually used as the gate electrodes due to its excellent electrocatalytic activity. In this paper, a cheap and biocompatible material, TiO2 nanotube arrays (TNTAs), was used as the gate electrode of the OECT device for the first time. It is encouraging that the sensing performance of OECTs using TNTAs-based gate electrodes is comparable to or better than those of the previously reported OECTs using Pt-based gate electrodes. Highly sensitive and selective OECT devices can be obtained by modifying TNTAs electrodes with Pt nanoparticles (Pt-NPs) and enzyme (glucose oxidase). The device shows a linear response to the logarithm of glucose concentration over the range from 100 nM to 5 mM, and the detection limit as low as 100 nM was achieved, which is three orders of magnitude lower than that of a conventional electrochemical measurement with the same electrode. On the other hand, the glucose can be selectively detected in the presence of interferences, such as ascorbic acid and uric acid, when the gate electrode is modified with Nafion. Moreover, the device presents a good stability and reproducibility. By modifying with other specific enzymes and nanomaterials, it is expected that many other type of enzyme sensors with high sensitivity and selectivity could be realized.
    Full-text · Article · Mar 2015 · Sensors and Actuators B Chemical
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    • "These features make OECTs particularly well suited for interfacing and studying cells. In fact, biological applications of OECTs have been recently proposed, dealing with: delivering neurotransmitters in vivo (Simon et al., 2009), electronically controlling ion signaling (Isaksson et al., 2007), controlling cell adhesion (Bolin et al., 2009; Wan et al., 2009) and migration (Gumus et al., 2010), measuring neuronal activity in vivo (Khodagholy et al., 2013), sensing of biomolecules (Kergoat et al., 2014; Lin et al., 2011; Tarabella et al., 2013b, 2012), and fabricating ion-based logic circuits (Tybrandt et al., 2012). Various examples of organic devices interfacing layers of mammalian cells have been recently described too, with applications in toxicology and diagnostic monitoring (Jimison et al., 2012; Lin et al., 2010; Ramuz et al., 2014; Tria et al., 2014; Yao et al., 2013). "
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    ABSTRACT: We propose and demonstrate a sensitive diagnostic device based on an Organic Electrochemical Transistor (OECT) for direct in-vitro monitoring cell death. The system efficiently monitors cell death dynamics, being able to detect signals related to specific death mechanisms, namely necrosis or early/late apoptosis, demonstrating a reproducible correlation between the OECT electrical response and the trends of standard cell death assays. The innovative design of the Twell-OECT system has been modeled to better correlate electrical signals with cell death dynamics. To qualify the device, we used a human lung adenocarcinoma cell line (A549) that was cultivated on the micro-porous membrane of a Transwell (Twell) support, and exposed to the anticancer drug doxorubicin. Time-dependent and dose-dependent dynamics of A549 cells exposed to doxorubicin are evaluated by monitoring cell death upon exposure to a range of doses and times that fully covers the protocols used in cancer treatment. The demonstrated ability to directly monitor cell stress and death dynamics upon drug exposure using simple electronic devices and, possibly, achieving selectivity to different cell dynamics is of great interest for several application fields, including toxicology, pharmacology, and therapeutics. Copyright © 2015 Elsevier B.V. All rights reserved.
    Full-text · Article · Feb 2015 · Biosensors & Bioelectronics
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