| 1. |
- Kongkaew, Supatinee, et al.
(författare)
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Craft-and-Stick Xurographic Manufacturing of Integrated Microfluidic Electrochemical Sensing Platform
- 2023
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Ingår i: Biosensors. - : MDPI. - 2079-6374. ; 13:4
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Tidskriftsartikel (refereegranskat)abstract
- An innovative modular approach for facile design and construction of flexible microfluidic biosensor platforms based on a dry manufacturing "craft-and-stick" approach is developed. The design and fabrication of the flexible graphene paper electrode (GPE) unit and polyethylene tetraphthalate sheet (PET)6/adhesive fluidic unit are completed by an economic and generic xurographic craft approach. The GPE widths and the microfluidic channels can be constructed down to 300 mu m and 200 mu m, respectively. Both units were assembled by simple double-sided adhesive tapes into a microfluidic integrated GPE (MF-iGPE) that are flexible, thin (<0.5 mm), and lightweight (0.4 g). We further functionalized the iGPE with Prussian blue and glucose oxidase for the fabrication of MF-iGPE glucose biosensors. With a closed-channel PET fluidic pattern, the MF-iGPE glucose biosensors were packaged and sealed to protect the integrated device from moisture for storage and could easily open with scissors for sample loading. Our glucose biosensors showed 2 linear dynamic regions of 0.05-1.0 and 1.0-5.5 mmol L-1 glucose. The MF-iGPE showed good reproducibility for glucose detection (RSD < 6.1%, n = 6) and required only 10 mu L of the analyte. This modular craft-and-stick manufacturing approach could potentially further develop along the concept of paper-crafted model assembly kits suitable for low-resource laboratories or classroom settings.
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| 2. |
- Kongkaew, Supatinee, et al.
(författare)
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Evaluation on the Intrinsic Physicoelectrochemical Attributes and Engineering of Micro-, Nano-, and 2D-Structured Allotropic Carbon-Based Papers for Flexible Electronics
- 2021
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:49, s. 14302-14313
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Tidskriftsartikel (refereegranskat)abstract
- Flexible electronics have gained more attention for emerging electronic devices such as sensors, biosensors, and batteries with advantageous properties including being thin, lightweight, flexible, and low-cost. The development of various forms of allotropic carbon papers provided a new dry-manufacturing route for the fabrication of flexible and wearable electronics, while the electrochemical performance and the bending stability are largely influenced by the bulk morphology and the micro-/nanostructured domains of the carbon papers. Here, we evaluate systematically the intrinsic physicoelectrochemical properties of allotropic carbon-based conducting papers as flexible electrodes including carbon-nanotubes-paper (CNTs-paper), graphene-paper (GR-paper), and carbon-fiber-paper (CF-paper), followed by functionalization of the allotropic carbon papers for the fabrication of flexible electrodes. The morphology, chemical structure, and defects originating from the allotropic nanostructured carbon materials were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, followed by evaluating the electrochemical performance of the corresponding flexible electrodes by cyclic voltammetry and electrochemical impedance spectroscopy. The electron-transfer rate constants of the CNTs-paper and GR-paper electrodes were similar to 14 times higher compared with the CF-paper electrode. The CNTs-paper and GR-paper electrodes composed of nanostructured carbon showed significantly higher bending stabilities of 5.61 and 4.96 times compared with the CF-paper. The carbon-paper flexible electrodes were further functionalized with an inorganic catalyst, Prussian blue (PB), forming the PB-carbon-paper catalytic electrode and an organic conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), forming the PEDOT-carbon-paper capacitive electrode. The intrinsic attribute of different allotropic carbon electrodes affects the deposition of PB and PEDOT, leading to different electrocatalytic and capacitive performances. These findings are insightful for the future development and fabrication of advanced flexible electronics with allotropic carbon papers.
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| 3. |
- Limbut, Warakorn, et al.
(författare)
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A comparative study of capacitive immunosensors based on self-assembled monolayers formed from thiourea, thioctic acid, and 3-mercaptopropionic acid
- 2006
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 22:2, s. 233-240
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Tidskriftsartikel (refereegranskat)abstract
- A procedure was developed for the covalent coupling of anti-alpha-fetoprotein antibody (anti-AFP) to a gold surface modified with a self-assembled monolayer (SAM) of thiourea (TU). The performance of the SAM-antibody layer was compared to those of similar layers based on thioctic acid (TA) and 3-mercaptopropionic acid (MPA) by using flow injection capacitive immunosensor system. Covalent coupling of anti-AFP on self-assembled thiourea monolayer (SATUM) modified gold electrode can be used to detect alpha-fetoprotein with high efficiency, similar sensitivity, the same linear range (0.01-10 mu g l(-1)) and detection limit (10ng l(-1)) as those obtained from sensors based on self-assembled thioctic acid monolayer (SATAM) and self-assembled 3-mercaptopropionic acid monolayer (SAMPAM). The system is specific for alpha-fetoprotein and can be regenerated and reused up to 48 times. Therefore, self-assembled monolayer using thiourea which is cheaper than thioctic acid and 3-mercaptopropionic acid is a good alternative for biosensor applications when SAMs are used. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Limbut, Warakorn, et al.
(författare)
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Capacitive biosensor for detection of endotoxin
- 2007
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 389:2, s. 517-525
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Tidskriftsartikel (refereegranskat)abstract
- A capacitive biosensor for the detection of bacterial endotoxin has been developed. Endotoxin-neutralizing protein derived from American horseshoe crab was immobilized to a self-assembled thiol layer on a biosensor transducer (Au). Upon injection of a sample containing endotoxin, a decrease in the observed capacitive signal was registered. Endotoxin could be determined under optimum conditions with a detection limit of 1.0 x 10(-13) M and linearity ranging from 1.0 x 10(-13) to 1.0 x 10(-10) M. Good agreement was achieved when applying endotoxin preparations purified from an Escherichia coli cultivation to the capacitive biosensor system, utilizing the conventional method for quantitative endotoxin determination, the Limulus amebocyte lysate test as a reference. The capacitive biosensor method was statistically tested with the Wilcoxon signed rank test, which proved the system is acceptable for the quantitative analysis of bacterial endotoxin (P < 0.05).
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| 5. |
- Malarat, Natchaya, et al.
(författare)
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Electropolymerization of poly(phenol red) on laser-induced graphene electrode enhanced adsorption of zinc for electrochemical detection
- 2024
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Ingår i: Talanta. - : ELSEVIER. - 0039-9140 .- 1873-3573. ; 272
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Tidskriftsartikel (refereegranskat)abstract
- We present a highly sensitive and selective electrode of laser-induced graphene modified with poly(phenol red) (P(PhR)@LIG) for measuring zinc nutrition in rice grains using square wave anodic stripping voltammetry (SWASV). The physicochemical properties of P(PhR)@LIG were investigated with scanning electron microscopy (SEM), energy -dispersive X-ray (EDX), Fourier infrared spectroscopy (FT-IR) and Raman spectroscopy. The modified electrode demonstrated an amplified anodic stripping response of Zn2+ due to the electropolymerization of P(PhR), which enhanced analyte adsorption during the accumulation step of SWASV. Under optimized parameters, the developed sensor provided a linear range from 30 to 3000 mu g L-1 with a detection limit of 14.5 mu g L-1. The proposed electrode demonstrated good reproducibility and good anti-interference properties. The sensor detected zinc nutrition in rice grain samples with good accuracy and the results were consistent with the standard ICP-OES method.
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| 6. |
- Promsuwan, Kiattisak, et al.
(författare)
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Bio-PEDOT: Modulating Carboxyl Moieties in Poly(3,4-ethylenedioxythiophene) for Enzyme-Coupled Bioelectronic Interfaces
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 12:35, s. 39841-39849
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Tidskriftsartikel (refereegranskat)abstract
- Modulation of chemical functional groups on conducting polymers (CPs) provides an effective way to tailor the physicochemical properties and electrochemical performance of CPs, as well as serves as a functional interface for stable integration of CPs with biomolecules for organic bioelectronics (OBEs). Herein, we introduced a facile approach to modulate the carboxylate functional groups on the PEDOT interface through a systematic evaluation on the effect of a series of carboxylate-containing molecules as counterion dopant integrated into the PEDOT backbone, including acetate as monocarboxylate (mono-COO-), malate as dicarboxylate (di-COO-), citrate as tricarboxylate (tri-COO-), and poly(acrylamide-co-acrylate) as polycarboxylate (poly-COO-) bearing different amounts of molecular carboxylate moieties to create tunable PEDOT:COO- interfaces with improved polymerization efficiency. We demonstrated the modulation of PEDOT:COO- interfaces with various granulated morphologies from 0.33 to 0.11 mu m, tunable surface carboxylate densities from 0.56 to 3.6 mu M cm(-2), and with improved electrochemical kinetics and cycling stability. We further demonstrated the effective and stable coupling of an enzyme model lactate dehydrogenase (LDH) with the optimized PEDOT:poly-COO- interface via simple covalent chemistry to develop biofunctionalized PEDOT (Bio-PEDOT) as a lactate biosensor. The biosensing mechanism is driven by a sequential bioelectrochemical signal transduction between the bio-organic LDH and organic PEDOT toward the concept of all-polymer-based OBEs with a high sensitivity of 8.38 mu A mM(-1) cm(-2) and good reproducibility. Moreover, we utilized the LDH-PEDOT biosensor for the detection of lactate in spiked serum samples with a high recovery value of 91-96% and relatively small RSD in the range of 2.1-3.1%. Our findings provide a new insight into the design and optimization of functional CPs, leading to the development of new OBEs for sensing, biosensing, bioengineering, and biofuel cell applications.
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| 7. |
- Soleh, Asamee, et al.
(författare)
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A wireless smartphone-based "tap-and-detect" formaldehyde sensor with disposable nano-palladium grafted laser-induced graphene (nanoPd@LIG) electrodes
- 2023
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Ingår i: Talanta. - : ELSEVIER. - 0039-9140 .- 1873-3573. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- We developed a fully integrated smart sensing device for on-site testing of food to detect trace formaldehyde (FA). A nano-palladium grafted laser-induced graphene (nanoPd@LIG) composite was synthesized by one-step laser irradiation of a symbolscript precursor. The composite was synthesized in the form of a three-electrode sensor on a polymer substrate. The electrochemical properties and morphology of the fabricated composite were characterized and the electrochemical kinetics of FA oxidation at the nanoPd@LIG electrode were investigated. The nanoPd@LIG electrode was combined with a smart electrochemical sensing (SES) device to determine FA electrochemically. The proposed SES device uses near field communication (NFC) to receive power and transfer data between a smartphone interface and a battery-free sensor. The proposed FA sensor exhibited a linear detection range from 0.01 to 4.0 mM, a limit of detection of 6.4 mu M, good reproducibility (RSDs between 2.0 and 10.1%) and good anti-interference properties for FA detection. The proposed system was used to detect FA in real food samples and the results correlated well with the results from a commercial potentiostat and a spectrophotometric analysis.
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| 8. |
- Teeparuksapun, Kosin, et al.
(författare)
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Disposable Electrodes for Capacitive Immunosensor
- 2009
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Ingår i: Electroanalysis. - : Wiley. - 1040-0397 .- 1521-4109. ; 21:9, s. 1066-1074
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Tidskriftsartikel (refereegranskat)abstract
- Disposable electrodes were fabricated by coating chromium (5 nm) and gold (200 nm) on glass strips (5.0 mm x 25.4 mm) and used in a label-free immunosensor. Human Serum albumin (HSA) and its antigen (anti-HSA) were used as a model system. Electropolymerization of o-phenylenediamine was used for the immobilization of anti-HSA by covalent binding. A linear relationship was obtained in the range from 1.0 x 10-(14) to 1.0 x 10-(19) M with a limit of detection of 8.0 x 10(-15) M. Each modified electrode can be reused up to 30 times. The developed system was applied for human serum samples and compared to Albumin BCG method.
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