| 1. |
- Larpant, Nutcha, et al.
(författare)
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Paper-Based Competitive Immunochromatography Coupled with an Enzyme-Modified Electrode to Enable the Wireless Monitoring and Electrochemical Sensing of Cotinine in Urine
- 2021
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Ingår i: Sensors. - : MDPI. - 1424-8220. ; 21:5
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a combined strategy of using paper-based competitive immunochromatography and a near field communication (NFC) tag for wireless cotinine determination. The glucose oxidase labeled cotinine antibody specifically binds free cotinine in a sample, whereas the unoccupied antibody attached to BSA-cotinine at the test line on a lateral flow strip. The glucose oxidase on the strip and an assistant pad in the presence of glucose generated H2O2 and imposed the Ag oxidation on the modified electrode. This enabled monitoring of immunoreaction by either electrochemical measurement or wireless detection. Wireless sensing was realized for cotinine in the range of 100–1000 ng/mL (R2 = 0.96) in PBS medium. Undiluted urine samples from non-smokers exhibited an Ag-oxidation rate three times higher than the smoker’s urine samples. For 1:8 diluted urine samples (smokers), the proposed paper-based competitive immunochromatography coupled with an enzyme-modified electrode differentiated positive and negative samples and exhibited cotinine discrimination at levels higher than 12 ng/mL. This novel sensing platform can potentially be combined with a smartphone as a reader unit.
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| 2. |
- Larpant, Nutcha, et al.
(författare)
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Sensing by wireless reading Ag/AgCl redox conversion on RFID tag : universal, battery-less biosensor design
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Massive integration of biosensors into design of Internet-of-Things (IoT) is vital for progress of healthcare. However, the integration of biosensors is challenging due to limited availability of battery-less biosensor designs. In this work, a combination of nanomaterials for wireless sensing of biological redox reactions is described. The design exploits silver nanoparticles (AgNPs) as part of the RFID tag antenna. We demonstrate that a redox enzyme, particularly, horseradish peroxidase (HRP), can convert AgNPs into AgCl in the presence of its substrate, hydrogen peroxide. This strongly changes the impedance of the tag. The presented example exploits gold nanoparticle (AuNP)-assisted electron transfer (ET) between AgNPs and HRP. We show that AuNP is a vital intermediate for establishing rapid ET between the enzyme and AgNPs. As an example, battery-less biosensor-RFID tag designs for H2O2 and glucose are demonstrated. Similar battery-less sensors can be constructed to sense redox reactions catalysed by other oxidoreductase enzymes, their combinations, bacteria or other biological and even non-biological catalysts. In this work, a fast and general route for converting a high number of redox reaction based sensors into battery-less sensor-RFID tags is described.
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| 3. |
- Pupinyo, Naricha, et al.
(författare)
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Impedimetric melanoma invasion assay device using a simple paper membrane and stencil-printed electrode on PMMA substrate
- 2020
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Ingår i: Sensing and Bio-Sensing Research. - : Elsevier BV. - 2214-1804. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- The transwell assay is currently the most popular approach to studying cellular invasion due to its ease of use and readout, and the possibility for quantitative measurements. However, it only allows end-point measurements without the possibility for real-time tracking of the dynamics of cell movement during an invasion. Moreover, it requires cell labeling, and construction of customized devices is hampered by the commercial standard membrane inserts, only available in certain designs. Recently, paper has been used as a scaffold for three-dimensional (3D) cell cultures. Because of its microfibrous structure and easy handling, it could be a versatile alternative as a membrane insert in customized devices. Here, we develop a low-cost real-time invasion assay device using paper as an alternative membrane insert. The device was designed for two-electrode impedance measurements and fabricated using CNC micromilling. It also comprised a disposable low-cost stencil-printed working electrode on a poly(methyl methacrylate) substrate below the membrane and glassy carbon counter electrode above the membrane inserted in a specially designed lid. Thus, the impedance measurements during cell invasion addressed the entire membrane. We demonstrated the function of the device by monitoring the invasion of B16 melanoma 4A5 cells from a mouse using insulin growth factor-1 as the chemoattractant. The cell invasion on paper was visualized using scanning electron microscopy and confocal microscopy with Z-stack 3D imaging. Melanoma cell invasion could be observed within 7 h after the chemoattractant treatment, which was faster than the conventional assay and less likely to be influenced by cell proliferation.
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| 4. |
- Thirabowonkitphithan, Pannawich, et al.
(författare)
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Detection of Pseudomonas aeruginosa infection using a sustainable and selective polydopamine-based molecularly imprinted electrochemical sensor
- 2024
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Ingår i: European Polymer Journal. - 0014-3057. ; 209
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Tidskriftsartikel (refereegranskat)abstract
- Pyocyanin, a redox-active secondary metabolite produced by Pseudomonas aeruginosa, serves as a crucial virulence factor. Detection and quantification of pyocyanin can aid early diagnosis of infection. A selective and sensitive molecularly imprinted electrochemical sensor was constructed by using a green polymerization technique to deposit an ultrathin polydopamine film on an electrode modified with gold nanoparticles and chitosan. Target recognition was facilitated by specific binding sites within the imprinted polymer matrix that are complementary to the structure of pyocyanin. Various techniques, including cyclic voltammetry, electrochemical impedance spectroscopy, and square wave voltammetry, were employed to characterize the electrochemical behavior of the sensor. We investigated the influence of fabrication components, including chitosan concentration, monomer concentration, electro-polymerization conditions, pH, and rebinding time. Demonstrating a high degree of specificity and sensitivity, the sensor showcased a broad linear detection range of 1–100 µM and a low detection limit of 0.74 µM for pyocyanin. Moreover, the sensor successfully detected pyocyanin in real bacterial culture samples, exhibiting a recovery of the spiked standard ranging from 93 to 103 %. The electrochemical sensor displayed satisfactory stability lasting for at least 5 weeks. We demonstrated the sensor's applicability for clinical measurements by detecting pyocyanin in infected burn wounds using an ex vivo porcine skin model. Leveraging the synergistic advantages of molecularly imprinted polymer and the specific redox window for pyocyanin detection, the electrochemical sensor presents a promising approach for early-stage infection identification, thus contributing to enhanced treatment and more effective healthcare for patients.
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| 5. |
- Thirabowonkitphithan, Pannawich, et al.
(författare)
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Electrogenicity of microbial biofilms of medically relevant microorganisms : potentiometric, amperometric and wireless detection.
- 2024
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- Since the progression of biofilm formation is related to the success of infection treatment, detecting microbial biofilms is of great interest. Biofilms of Gram-positive Staphylococcus aureus and Streptococcus gordonii bacteria, Gram-negative Pseudomonas aeruginosa and Escherichia coli bacteria, and Candida albicans yeast were examined using potentiometric, amperometric, and wireless readout modes in this study. As a biofilm formed, the open circuit potential (OCP) of biofilm hosting electrode (bioanode) became increasingly negative. Depending on the microorganism, the OCP ranged from −70 to −250 mV. The co-culture generated the most negative OCP (−300 mV vs Ag/AgCl), while the single-species biofilm formed by E. coli developed the least negative (−70 mV). The OCP of a fungal biofilm formed by C. albicans was −100 mV. The difference in electrode currents generated by biofilms was more pronounced. The current density of the S. aureus biofilm was 0.9‧10−7 A cm−2, while the value of the P. aeruginosa biofilm was 1.3‧10−6 A cm−2. Importantly, a biofilm formed by a co-culture of S. aureus and P. aeruginosa had a slightly higher negative OCP value and current density than the most electrogenic P. aeruginosa single-species biofilm. We present evidence that bacteria can share redox mediators found in multi-species biofilms. This synergy, enabling higher current and OCP values of multi-species biofilm hosting electrodes, could be beneficial for electrochemical detection of infectious biofilms in clinics. We demonstrate that the electrogenic biofilm can provide basis to construct novel wireless, chip-free, and battery-free biofilm detection method.
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