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Supramolecular electrochemical detection of bisphenol A using a melamine-functionalized reduced graphene oxide modified screen-printed electrode
(2026-06-01)
Thammaso, Supinya
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Kamsong, Wichayaporn
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Karuwan, Chanpen
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Saetear, Phoonthawee
;
Detsri, Ekarat
Detection of bisphenol A (BPA), an endocrine disruptor, requires rapid and reliable methods to ensure water safety. In the current work, we present a supramolecular electrochemical sensor based on a melamine-immobilized reduced graphene oxide-modified screen-printed carbon electrode (Mel-rGO SPE) for the determination of BPA. The sensing design exploits dual supramolecular interactions: hydrogen bonding between melamine's amine groups and BPA's hydroxyl moieties, and π–π stacking between their aromatic rings. While rGO significantly enhances electron transfer, these synergistic effects improve device sensitivity. A Mel-rGO SPE was fabricated using an ink-mixing approach to produce a uniform and robust sensor. BPA detection was performed using cyclic voltammetry, and the anodic peak potential was 0.32 V. The current response provided a good correlation with BPA concentrations in the range of 1–250 μM. The detection limit was low, 0.23 μM. The Mel-rGO SPE was successfully applied to determine BPA in polycarbonate bottled water. These promising results indicate that the developed sensor is an alternative device for rapid screening of BPA contamination of water samples.
2
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IFITMs exhibit antiviral activity against Chikungunya and Zika virus infection via the alteration of TLRs and RLRs signaling pathways
(2025-12-01)
Gumpangseth, Nuttamonpat
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Villarroel, Paola Mariela Saba
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Diack, Abibatou
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Songhong, Thanaphon
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Yainoy, Sakda
Chikungunya virus (CHIKV) poses a significant challenge as there are currently no targeted antiviral drugs or vaccines to combat this infection. Here, we demonstrate that interferon-induced transmembrane proteins (IFITMs), including IFITM1, IFITM2, and IFITM3, which are interferon-stimulated genes (ISGs), inhibit CHIKV infection in human skin fibroblasts. Overexpression of IFITMs in cells restricts viral infection, whereas knockdown of IFITMs enhances viral infection. IFITMs overexpression causes a substantial upregulation of antiviral genes, namely TLR3, TLR7, TLR8, and TLR9, and their downstream signaling molecules such as TRADD, IRAK1, TRAF6, and MAP3K7, involved in TLRs signaling pathways. Furthermore, the DHX58 gene encoding the LGP2 protein, a negative regulator of RIG-I in RLRs signaling pathways, was downregulated in the overexpressed cells. Transcription factors including interferon regulatory factors (IRF) 3/5/7, which are downstream signaling components of both TLR and RLR signaling pathways, were also upregulated, resulting in enhanced IFNs signaling. IFITMs not only inhibits the early and late stages of viral infection but can also alter the antiviral innate-immune response to restrict CHIKV infection in human skin fibroblasts. Additionally, IFITMs exhibit their antiviral activity against Zika virus (ZIKV). Altogether, these results show the broad-spectrum antiviral property of IFITMs against arboviruses in foreskin cells.
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Hydrophobic barrier-free laminated paper-based analytical device (LPAD) using a diameter-based measurement for determination of iodide in pharmaceutical products
(2024-08-01)
Noirahaeng, Nakarin
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Salungyu, Jirawat
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Teerasong, Saowapak
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Uraisin, Kanchana
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Saetear, Phoonthawee
This work presents, for the first time, an exploitation of an argentometric Mohr's method for iodide detection using diameter-based measurement on laminated paper-based analytical device (LPAD). Our LPAD is simplified fabricated with no required hydrophobic barrier for patterning a detection flow channel. In the absence of a flow channel, the liquid is imbibed radially into the filter paper outward from the small center inlet hole. This imbibition leads to the measurement of diameter after the formation of the precipitation product. For LPAD, a rectangular piece of Whatman filter paper is cut and positioned between a top laminating sheet, which has a hole punched for inlet, and a bottom laminating sheet. The central inlet hole enables access to the liquid on the paper. For iodide analysis, silver nitrate is dispensed first, followed by the iodide standard/sample. This process leads to the formation of pale-yellow silver iodide solids on the paper. The chromate indicator solution is subsequently loaded to the paper. The color of the chromate solution imparts a tint to the circular band of silver iodide solids, resulting in an intense yellow color. When the silver iodide precipitates are stained, the chromate solution typically serves as an indicator, chemically reacting to an excess silver nitrate solution moistened on paper. This reaction generates an outer reddish-brown ring of silver chromate. The distinct color contrast between the intense yellow (tinted silver iodide) and reddish-brown (silver chromate) allows for clear observation of the measurement boundary, facilitating diameter-based measurements of the circular band of silver iodide. We demonstrate the applicability in analysis of pharmaceutical KI tablets. The quantitative results obtained from diameter-based measurement LPAD show good agreement with those obtained from the potentiometric method. Our hydrophobic barrier-free LPAD is rapid, cost-effective, low liquid consumption and applicable for onsite analysis.
2
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A rapid cotton swab for on-site screening of coloring curcumin on durian skin: food safety aspects
(2023-08-01)
Teerasong, Saowapak
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Boonyaratsewee, Phanaporn
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Aunruan, Panuwat
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Saard, Worawan
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Saetear, Phoonthawee
Exported durians from Thailand are sometimes immersed in curcumin to give the fruits a good appearance. Curcumin is regarded as non-toxic additive, however some importing countries prohibited use of any additive to fresh fruits and vegetables. This work aims to develop a rapid, low cost and convenient cotton swab device for curcumin detection. The detection principle involves a colorimetric acid–base characteristic of curcumin. Curcumin in an acidic/neutral solution presents a bright yellow color, while it displays an intense orange–red color in basic solution. A cotton swab acted for both sample collection and as a sensing platform. A pre-moistened swab was used to wipe a durian surface. Afterward, a NaOH solution was dropped onto the swab. A distinct orange–red color appearing on the swab indicates the presence of curcumin. The cotton swab was applied for qualitative analysis of curcumin contaminated on durian husks via visual detection. The developed device provided good reliability, 93.75% (36 samples). Furthermore, the device was demonstrated for quantitative determination using camera detection. Two linear calibrations were obtained in ranges of 10–75 and 75–250 mg L−1, with a detection limit of 3.2 mg L−1. The method was also successfully applied to quantification of curcumin in durians (three samples) and dietary supplements (two samples). The test can be done in a few minutes. The developed device was established as an useful tool for food safety and control of contamination by curcumin in an on-site application. Graphical abstract: [Figure not available: see fulltext.]
2
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Transparent Cross-Flow Platform as Chemiluminescence Detection Cell in Cross Injection Analysis
(2023-02-01)
Somboonsuk, Thachkorn
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Saetear, Phoonthawee
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Mantim, Thitirat
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Ratanawimarnwong, Nuanlaor
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Wilairat, Prapin
This work presents the use of a transparent ‘Cross Injection Analysis’ (CIA) platform as a flow system for chemiluminescence (CL) measurements. The CL-CIA flow device incorporates introduction channels for samples and reagents, and the reaction and detection channels are in one acrylic unit. A photomultiplier tube placed above the reaction channel detects the emitted luminescence. The system was applied to the analysis of (i) Co(II) via the Co(II)-catalyzed H<inf>2</inf>O<inf>2</inf>-luminol reaction and (ii) paracetamol via its inhibitory effect on the catalytic activity of Fe(CN)<inf>6</inf>3− on the H<inf>2</inf>O<inf>2</inf>-luminol reaction. A linear calibration was obtained for Co(II) in the range of 0.002 to 0.025 mg L−1 Co(II) (r2 = 0.9977) for the determination of Co(II) in water samples. The linear calibration obtained for the paracetamol was 10 to 200 mg L−1 (r2 = 0.9906) for the determination of pharmaceutical products. The sample throughput was 60 samples h−1. The precision was ≤4.2% RSD. The consumption of the samples and reagents was ca. 170 µL per analysis cycle.
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